Treatments for retinal disorders

ABSTRACT

The present invention relates to the use of cyclic oligosaccharides as chemical complexants of lipofuscin bisretinoids (A2E) to prevent and treat eye (i.e., retinal or macular) disease. Monomeric, dimeric, multimeric, or polymeric oligosaccharide rings act as pharmacologic agents to prevent and treat ophthalmologic disorders triggered by the accumulation of lipofuscin in the retinal pigment epithelium (RPE), which occurs as a consequence of either genetic disorders, such as Stargardt Disease (SD) and Best Disease (BD), or aging, such as Age-Related Macular Degeneration (AMD), or other diseases, such as retinitis pigmentosa, and cone-rod dystrophy.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 13/980,687 filed on Oct. 8, 2013, which is a National Stage Entry ofApplication No. of PCT/US2012/021997 filed on Jan. 20, 2012, whichclaims the benefit of priority from U.S. Provisional Application No.61/434,585, filed on Jan. 20, 2011.

GOVERNMENT SUPPORT

This invention was made with government support under GM079238 awardedby the National Institutes of Health. The government has certain rightsin the invention.

FIELD OF THE INVENTION

The present invention relates, generally, to methods for treatingretinal diseases and conditions, and more particularly, to the treatmentof retinal diseases and conditions caused by accumulation ofbisretinoids, such as age-related macular degeneration and relateddisorders.

BACKGROUND OF THE INVENTION

The human eye is designed so that light traverses the anterior portions(cornea, aqueous humor and lens), the vitreous and the anterior layersof the retina before reaching the outer segments of light-sensitivecells or photoreceptors (PROS), i.e., the rods and cones. FIG. 1Aprovides a general schematic of the retinal components.

Light not absorbed by the visual pigments in PROS (e.g., rhodopsin inrods, various opsins in cones) is absorbed by the adjacent retinalpigment epithelial cells (RPE), which is highly pigmented, andtherefore, functions as a dark chamber. Located at the interphasebetween photoreceptor (PR) and the choroidal blood vessels, the RPEperforms key support functions for PR. These include: (i) providing keyblood nutrients through various RPE transporters (e.g., glucose,aminoacids); (ii) maintaining the ionic composition of the subretinalspace (space between RPE and PR) through sophisticated transportmechanisms; (iii) participating in the “visual cycle” (FIG. 1B), byre-isomerizing a key lipid, cis-retinal, which intimately associateswith rhodopsin and is the acceptor for photons; and (iv) phagocytosis(i.e., “eating up and digestion of”) PR outer segments, a key aspect ofthe renewal of the retina. In the visual cycle, light impinges oncis-retinal and converts it into trans-retinal, which is quicklyconverted into an alcohol derivative (cis-retinol), which is transportedto the RPE for regeneration of cis-retinal. All of these RPE functionsare essential for normal vision.

Unlike other epithelial cells, which regenerate themselves continuouslythrough cell division, RPE cells do not divide, and therefore, are moresusceptible to accumulation of materials as they age. One RPE celldisposes the debris generated by 30-50 adjacent PR cells. This debris isproduced by circadian shedding of PR tips, the oldest part of PROS.

The daily and heavy phagocytic activity of RPE cells results in theaccumulation of lipofuscin in their digestive system, i.e., theendo-lysosomal apparatus. Lipofuscin accumulation is a universal andphylogenically conserved marker of aging (Sohal, R. S., Age Pigments,Elsevier Science Ltd., © 1981). All metabolically active post-mitoticcells, including cardiac myocytes, neurons, and RPE cells, showage-related accumulation of lipofuscin within their lysosomal system.For most of these cells, the lipofuscin originates primarily from theincomplete degradation of exhausted organelles (autophagy). Dependingupon the tissue analyzed, lipofuscin granules normally have 30-70% ofprotein content (Sohal, Ibid.). In striking contrast, the lipofuscindeposits of aged RPE cells contain almost no protein (<2%); rather, theyare constituted of lipidic pigment derivatives of trans-retinal,generated by the visual cycle (Ng, K. P., et al., Mol. Cell Proteomics,7(7), pp. 1397-405, 2008). The most abundant and toxic lipidic pigmentsfound are the bisretinoids, primarily A2E, followed by A2E isomers,oxidized derivatives of A2E, A2-dihydropyridine-phosphatidylethanolamine(A2-DHP-PE), and smaller quantities of other Vitamin A conjugatesbelonging to the all-trans-retinal dimer series (Sparrow, J. R., et al.,Exp. Eye Res., 80(5), pp. 595-606, 2005). The non-enzymatic pathwayleading to the formation of these bisretinoids has been elucidated. FIG.1C provides a general overview of the bisretinoid pathways.

A2E-lipofuscin accumulates linearly with age because this material isrefractory to lysosomal enzyme degradation. Beyond a certain threshold,A2E-lipofuscin becomes toxic to RPE cells, which eventually results intheir malfunction and death. This deterioration process results in thedecrease or loss of the ability of RPE cells to support adjacent PRcells. Loss of PR cells resulting from the toxic effects of lipofuscinon RPE cells is considered a central pathogenetic mechanism in geneticand age-related retinal degenerations.

Age-related macular degeneration (AMD) is the most common cause ofblindness, affecting 36% of Americans in their eighth decade of life,with a devastating decrease in their quality of life (De, S., et al., J.Gen. Physiol., 120(2): pp. 147-57, 2002). Moreover, clinical evidenceshows that photoreceptors overlying bisretinoid-loaded RPE areas(containing mostly A2E) are the most prone to degeneration (Holz, F. G.,et al., Invest. Ophthalmol. Vis. Sci., 42(5): p. 1051-6, 2001). Althoughdecades are generally required for the natural accumulation of A2E inRPE, in some human genetic afflictions, like Stargardt Disease (SD) andBest Disease (BD), A2E reaches pathogenic levels typically by about 30years of age, typically resulting in blindness in the fourth decade oflife.

Lipofuscin-containing A2E has been shown harmful to RPE cells (Sparrow,J. R., et al., Adv. Exp. Med. Biol., 703: p. 63-74, 2010; Fernandes, A.F., et al., J. Biol. Chem., 283(30): pp. 20745-53, 2008; Lakkaraju, A.,et al., Proc. Natl. Acad. Sci. U.S.A., 104(26): pp. 11026-31, 2007).Three mechanisms have been postulated as contributing to A2E-mediatedRPE-toxicity: (1) the A2E's predisposition to oxidation, which can bespontaneous or light-induced and leads to the formation of reactiveoxygen species (ROI); (2) A2E's detergent properties, i.e.,intercalation of A2E into lysosomal membranes leads to interference ofcholesterol extrusion and accumulation of cholesterol, as observed incholesterol storage diseases such as Niemann Pick; and (3) A2E'stendency to form hydrophobic crystals, which are most likely detected byinnate immune receptors and trigger inflammation.

A2E and its derivatives have intrinsic fluorescence and account for mostof RPE-lipofuscin (RPE-LF) autofluorescence (Sparrow, J. R., et al.,Invest. Ophthalmol. Vis. Sci., 40(12): pp. 2988-95, 1999). Thefluorescence emission of A2E is influenced by the polarity of theenvironment in which the molecule is immersed (Sparrow, et al., 1999,Ibid.; Ragauskaite, L., et al., Photochem. Photobiol., 74(3): p. 483-8,2001; De, et al., 2002, Ibid.). Thus, in water, A2E maximally emits at610 nm, but in non-polar solvents, such as n-butyl chloride, A2Etypically exhibits a blue-shifted maximum of 585 nm (Sparrow et al.,1999, Ibid.). The emission maxima of A2E inside RPE cells is generallybetween 565 and 570 nm (Sparrow, et al., 1999, Ibid.;Haralampus-Grynaviski, N. M., et al., Proc. Natl. Acad. Sci. U.S.A.,100(6): p. 3179-84, 2003). This fluorescence spectrum suggests that,when inside a cell, A2E is tightly protected against the solvatochromicshift caused by water molecules (Sparrow, et al., 1999, Ibid.).Moroever, it is known that, with aging, the RPE-LF fluorescence shiftseven more toward blue, suggesting that with time A2E deposits may adoptstiffer organization inside these granules (Delori, F. C., et al.,Invest. Ophthalmol. Vis. Sci., 36(3): pp. 718-29, 1995).

High-magnification transmission electron-microscopy (TEM) has revealedthat A2E deposits are housed within the interior of discretemembrane-bound organelles that are uniformly dense, roughly spherical,and approximately 1 micrometer in diameter (Haralampus-Grynaviski, etal., 2003, Ibid.; Bindewald-Wittich, A., et al., Invest. Ophthalmol.Vis. Sci., 47(10): pp. 4553-7, 2006). Data obtained using atomic forcemicroscopy and purified granules has revealed that the bulk of A2Edeposits in RPE cells reside in the lumen of these post-lysosomalbodies, forming an orderly aggregated structure (Ng, et al., 2008,Ibid.; Sparrow, et al., 1999, Ibid.). Because of their ultrastructuralappearance, A2E-containing formations are sometimes also referred to as“lipofuscin granules”.

Some studies have predicted that positively-charged amphipathic lipidswith cone-shaped molecular geometry, like A2E, can self-assemble inwater as an inverted hexagonal phase creating large hydrophobicsemi-crystaline constructions (Seong, S. Y., et al., Nat. Rev. Immunol.,4(6): pp. 469-78, 2004; Klymchenko, A. S., et al., Nanoscale, 2(9): pp.1773-80, 2010). Significantly, highly repetitive hydrophobic structuresare known to be among the strongest inducers of chronic inflammation(Seong, et al., 2004, Ibid.). For example, monosodium urate, silicacrystals, and asbestos are known to form hydrophobic crystals that arehighly pro-inflammatory (Martinon, F., et al., Annu. Rev. Immunol., 27:pp. 229-65 (2009); Martinon, F., et al., Immunol. Rev., 233(1): pp.218-32, 2010; Martinon, F., Curr. Rheumatol. Rep., 12(2): pp. 135-41(2010); Dostert, C., et al., 320(5876): pp. 674-7, 2008).

Current therapeutic approaches aimed at alleviating vision loss andretinal (for example, macular) diseases associated with A2E accumulationgenerally rely on retarding A2E formation by drugs or viral-based genedelivery methods. Current drug therapy generally involves decreasingall-trans-retinal formation, which generally causes sight loss,including night blindness, as a side effect (Zarbin, M. A., et al.,Retina, 30(9): pp. 1350-67, 2010). Current gene therapy approachesgenerally involve delivering the WT gene to individuals with geneticmutations, but this approach is not applicable to AMD. Significantly,neither of these methodologies has been shown to effectively retard orreverse the accumulation of A2E once such accumulation has occurred.

SUMMARY OF THE INVENTION

The instant application is foremost directed to a method for thetreatment or prevention of lipofuscin-associated macular damage thatdoes not rely on decreasing trans-retinal formation or gene therapyapproaches of the art. Accordingly, the instant invention provides analternative and effective method for the treatment of AMD and relateddiseases and conditions without the known significant drawbacks of themethodologies of the art.

The methodology described herein achieves this improvement by employingcyclic oligosaccharide complexants (i.e., hosts, encapsulants,sequestrants, or binders) of lipofuscin bisretinoid lipids thatstabilize and reduce lipofuscin bisretinoid lipid levels in RPE cellswith minimal or no disruption in cell vitality. Moreover, the cyclicoligosaccharides described herein advantageously possess little or notoxicity associated with their use.

In the method, a cyclic oligosaccharide, which may be a monomer, dimer,multimer (e.g., trimer, tetramer, pentamer, hexamer, heptamer, octamer),or polymer thereof, is directed to (i.e., targets) RPE cells, where theyfunction as chemical complexants of the main constituents ofRPE-lipofuscin, i.e., A2E and iso-A2E and derivatives and modified formsthereof, for the treatment or prevention of lipofuscin-mediated retinaldeterioration. Specifically, the cyclic oligosaccharides form guest-hostcomplexes with A2E or a modified form thereof by incorporating A2E or amodified form thereof in the less hydrophilic (i.e., hydrophobic)binding pocket (i.e., cavity) of the cyclic oligosaccharide. As A2E orits modified form is substantially shielded and protected when complexedin the relatively hydrophobic cavity of the cyclic oligosaccharide, thecyclic oligosaccharide substantially diminishes or even completelyprevents A2E oxidation. As further discussed below, the use of cyclicoligosaccharides, even at high doses, has herein been found to notcompromise the well-being of RPE cells while dissolving A2E crystals andreducing overall A2E levels in RPE cells.

The instant application is also directed to an assay method foridentifying a compound that binds to a lipofuscin bisretinoid lipid.Thus, the method can be particularly instrumental in identifying acompound that can treat or prevent lipofuscin-associated macular damage,or a disease or condition associated therewith.

The assay method generally includes the following steps: (i) providingat least two solutions containing a lipofuscin bisretinoid lipid,wherein the at least two solutions are substantially the same in allrespects; (ii) adding a candidate compound to one of the solutions;(iii) measuring fluorescence spectra of the two solutions within awavelength range of 530 nm to 700 nm at an excitation wavelength thatcauses fluorescence of the lipofuscin bisretinoid lipid within saidwavelength range; (iv) determining an area under corresponding spectralcurves for each of the two solutions in said wavelength range; and (v)determining the ratio of the area under the spectral curve for thesolution holding the candidate compound relative to the area under thespectral curve for the solution not holding the candidate compound. Inthe assay method, a ratio greater than 1 indicates that the candidatecompound has bound with the lipofuscin bisretinoid lipid. Thus, a ratiogreater than 1 indicates that the candidate compound has potential as aneffective medicinal agent for treating or preventinglipofuscin-associated macular damage or a disease or conditionassociated therewith.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A: A graphical representation of components of the retina.

FIG. 1B. A general schematic of the light cycle.

FIG. 1C. A general schematic of the non-enzymatic pathway leading to theformation of bisretinoids.

FIG. 2. Drawing showing some examples of different types of moleculescontaining cyclic oligosaccharides: monomeric (A), dimeric (B), andmultimeric (C) cyclic oligosaccharides. The multimeric molecule maycontain the same or different cyclic oligosaccharides, and linkages canbe formed in a variety ways. Each conic section represents a cyclicoligosaccharide unit and each curved line represents a linking group.

FIGS. 3A-3C. FIG. 3A: Drawing of an exemplary multimeric or polymericstructure of linked cyclic oligosaccharides, wherein C represents one ormore type of the cyclic oligosaccharides, L represents a linker, andeach X represents a cell-targeting agent, such as M6P or one or moreprotonable nitrogenated groups similar to, but not limited to thosefound in lysosomotropic agents (chloroquine, lysotrackers, lysosensors,etc.). The dashed line to X indicates that these groups may or may notbe present, and, if present, may be attached to any portion of the groupto which they are bound. FIG. 3B: Generalized depictions of acomposition having an active portion therein that includes two or moredimers of cyclic oligosaccharide rings (multimer). Dimers can beidentical or, alternatively, may be composed of more than one type ofcyclic oligosaccharide. R may represent streptavidin, polymers, ormultimerizing agents that facilitate the organization of dimers intandem.

FIG. 4. Schematic showing general methodology used for measuring A2Efluorescence emission when A2E is dissolved in different solvents havingdifferent solvent polarities (left), and graph showing corresponding A2Efluorescence changes according to solvent polarity (right).

FIG. 5. Schematic showing general methodology used for measuring A2Efluorescence emission when A2E is combined with different cyclodextrins,i.e., alpha-cyclodextrin, beta-cyclodextrin, and gamma-cyclodextrin at10 mM cyclodextrin concentrations (left), and graph (right) showingcorresponding A2E fluorescence changes in the presence or absence ofthese cyclodextrins.

FIG. 6. Bar chart comparing the area under curve (AUC) for spectralfluorescence curves found for each of 21 cyclodextrins listed in Table 1using the same kind of methodology outlined in FIG. 5. The numbers inthe x-axis correspond to the compound numbers listed in Table 1. Arelative AUC value greater than 1 indicates binding of the cyclodextrinto A2E, which is an indicator of positive efficacy of the cyclodextrinfor removing A2E from RPE cells.

FIGS. 7A, 7B. Results for three of the leading cyclodextrins (CDs)identified to form complexes with A2E. FIG. 7A (top): Fluorescencespectra of these compounds. FIG. 7A (bottom): structure of the solublepolymeric beta-cyclodextrin (Poly B) used. FIG. 7B (top): Chart showingthe relative AUC of these CD compounds. FIG. 7B (bottom): Structures ofthe two dimeric beta-cyclodextrins. FIG. 7C: Detailed structure for CDidentified as SB276dim. FIG. 7D: Detailed structure for CD identified asSB176dim.

FIGS. 8A-8D. Drawings depicting: alpha-cyclodextrin (FIG. 8A),beta-cyclodextrin (FIG. 8B), gamma-cyclodextrin (FIG. 8C) screened forinteraction with A2E, as well as an exemplary structure (FIG. 8D) of themultimeric cyclodextrins that interacted most strongly with A2E. CD inFIG. 8D is preferably either a beta- or gamma-cyclodextrin.

FIG. 9A. Structures of cholesterol and dehydroergosterol (DHE) (top),and fluorescence emission results of method utilized to measure theaffinity of cyclodextrins for A2E as compared with results measuring theaffinity of the cyclodextrins to the fluorescent cholesterol analog DHE(bottom).

FIG. 9B. Chart plotting the fluorescence emission results of FIG. 9A asa function of CD:fluorophore ratio.

FIG. 10. Measurement of the affinity of cyclodextrins for A2E using theBenesi-Hildendrand method. The method utilized to measure the affinityof cyclodextrins for A2E was also used comparatively to measure theiraffinity for DHE, a fluorescent analog of cholesterol. The K_(d)s oflead compounds shown in FIG. 7 are displayed in the table in the lowerright.

FIG. 11. In silico modeling structures of A2E and beta-cyclodextrinusing PyMol software (top), and possible modes in which a cyclodextrinmonomer, dimer, or multimer may bind with A2E (bottom). The foregoinganalysis predicts higher stability of A2E cyclodextrin complexes whentwo or more oligosaccharide rings interact with A2E.

FIGS. 12A, 12B. Absorption spectra of normal and oxidized A2E (FIG.12A), and absorption spectra of A2E under oxidizing conditions in thepresence or absence of beta-cyclodextrin (FIG. 12B). As shown in FIG.12B, after 48 hours in aqueous phase, A2E is oxidized, whereas whenincubated in the presence of increasing levels of beta-cyclodextrin(10-100 mM) oxidation of A2E was not observed.

FIGS. 13A-13C. Results showing that cyclic oligosaccharides dissolve A2Eaggregates that form in aqueous phase. FIG. 13A: Predicted size (<0.005um) of A2E molecule based on its molecular weight of 596 (top), andDifferential Interference Contrast (DIC) microscopy (bottom), combinedwith fluorescence microscopy, which shows that A2E aggregates that formin aqueous phase (left panel) and within cells (right panel) are in themicron range size. FIG. 13B: General schematic of experimentdemonstrating that A2E aggregates cannot diffuse through transwellchambers with 0.4 μm pores but diffuse through transwell chambers with 3μm pores. FIG. 13C: Results showing that addition of beta-cyclodextrinto the aqueous phase dissolved the A2E aggregates, thus showing that A2Ecan diffuse through 0.2 μm pores.

FIGS. 14A-14D. Micrographs showing that multimeric beta-cyclodextrinscan reduce the levels of A2E in RPE cells. ARPE-19 cells were loadedwith A2E for 48 hrs, and washed and treated with 1 mM cyclodextrin for72 hours. A2E fluorescence was pictured in an spinning disk microscopeusing adequate filter sets. Micrographs for mock-loaded andmedia-treated (FIG. 14A), mock-loaded and CD-treated (FIG. 14B),A2E-loaded and media-treated (FIG. 14C), and A2E-loaded and CD-treated(FIG. 14D).

FIGS. 15A, 15B. CDs can reduce A2E levels in highly confluent, wellpolarized, epithelia. FIG. 15A outlines the experimental conditions.FIG. 15B shows images of the treated and untreated confluent cells underfluorescent and white light conditions. Panel A shows control epithelialcells loaded with A2E (bright fluorescence). Panel C shows polarizedepithelium treated with CDs after 24 h. The loss of fluorescent pigmentsis notable. Panels B and D are images of the same epithelia illuminatedwith white light to demonstrate that their integrity is not compromisedby treatment with CDs.

FIGS. 16A, 16B. CD-treatment of DKO mice reduces fundus, drusen andautofluorescence. FIG. 16A depicts the experimental conditions foradministering CDs and obtaining fundus images. FIG. 16B shows fundusimages obtained from eight month old WT control (A), DKO (B) andCD-treated DKO (C) mice. Note clear dots (drusen) in color fundus of DKOthat are reduced by CD treatment (compare A, B and C). Autofluorescencefundus images from WT control (D), DKO (E) and CD-treated DKO (F). Thenumbers indicate total amount of auto-fluorescence per mouse retina,which is a direct readout of the content of bisretionoids in RPE.

FIGS. 17A, 17B. FIG. 17A shows the general in vitro methodology in whicheyes from DKO mice were enucleated and dissected to separate cornea,lens, iris and neuroretina from the posterior part of the eye (eyecups).The resulting eyecups were in vitro treated with cyclodextrins for 36hrs before observing them under the microscope (FIG. 17B).

FIG. 18. Micrographs showing the fluorescence of cryosected retinas of8-months old WT and DKO mice. The micrographs obtained from (A) a normalmouse, (B) DKO animals not treated with methyl beta-CD, and (C) DKOanimals treated with methyl beta-CD. The DKO animals have strongautofluorescence in the RPE layer compared with WT as well as retinaldetachment (size shown by arrow). Single subtenon administration ofmethyl Beta CD (4000 mg/kg) reduced both RPE autofluorescence andretinal detachment.

DETAILED DESCRIPTION OF THE INVENTION

In one aspect, the invention is directed to a method for treating asubject suffering from or at risk of lipofuscin-associated damage or adisease or condition associated therewith. Conditions and diseasestreatable by the method described herein include any ophthalmologic orretinal disorder, condition, or disease directly or indirectly caused bythe accumulation of lipofuscin in retinal pigment epithelium (RPE)cells, which may be genetic or non-genetic, such as age-related maculardegeneration (AMD), Stargardt disease (SD), Best disease (BD), retinitispigmentosa, and cone-rod dystrophy.

The term “treatment” is intended to encompass any beneficial orameloriating effect on lipofuscin-associated damage or associateddisease or condition directly or indirectly caused by the accumulationof lipofuscin bisretinoid lipid in RPE cells. Thus, the term “treatment”may also include prevention of lipofuscin-associated damage or a diseaseor condition directly or indirectly associated withlipofuscin-associated damage or the accumulation of lipofuscin in RPEcells in a subject that is at risk of (i.e., not yet suffering from)lipofuscin-associated damage or accumulation, or a disease or conditiondirectly or indirectly associated therewith. The term “treatment” mayalso include prophylaxis, therapy, and/or cure.

Generally, the treatment considered herein has the effect of stopping,mitigating, or reversing the accumulation of lipofuscin bisretinoidlipid in RPE cells, and likewise, stopping, mitigating, or reversing thelipofuscin-associated damage or associated disease or condition. Themethod accomplishes this by complexing and removing lipofuscinbisretinoid lipid in RPE cells using cyclic oligosaccharides ascomplexing hosts (i.e., complexants). The cyclic oligosaccharidesconsidered herein possess a cavity (i.e., binding pocket) suitable foraccepting at least one lipofuscin bisretinoid lipid molecule as a guest.The result is a host-guest complex between the host cyclicoligosaccharide and guest lipofuscin bisretinoid lipid molecule. Asknown in the art, the interaction between host and guest is generally ofa non-covalent nature, such as by hydrogen-bonding and/or van der Waals(dispersion) forces. The lipofuscin bisretinoid lipid is generally A2E,an A2E isomer, an oxidized derivative of A2E,A2-dihydropyridine-phosphatidylethanolamine, or an all-tran-sretinaldimer.

In a first embodiment, the subject suffers from lipofuscin-associateddamage or a disease or condition directly or indirectly associatedtherewith, and the method prevents the lipofuscin-associated damage or adisease or condition associated therewith from worsening. In a secondembodiment, the subject suffers from lipofuscin-associated damage or adisease or condition directly or indirectly associated therewith, andthe method reverses (i.e., lessens or completely removes) thelipofuscin-associated damage or a disease or condition directly orindirectly associated therewith. In a third embodiment, the subject doesnot yet suffer from lipofuscin-associated damage or a disease orcondition directly or indirectly associated therewith, and the methodprevents, slows the onset, or lessens the severity oflipofuscin-associated damage or a disease or condition directly orindirectly associated with lipofuscin-associated damage or lipofuscinaccumulation in RPE cells. The latter embodiment is particularlydirected to a subject who is at risk, as determined by a medicalprofessional, of lipofuscin-associated damage or a disease or conditiondirectly or indirectly associated therewith or with lipofuscinaccumulation in RPE cells.

The subject (i.e., patient) receiving the treatment is an animal,generally a mammal, particularly a human. Non-human animals includes allvertebrates, e.g., mammals and non-mammals, such as non-human primates,sheep, dogs, cats, cows, horses, chickens, amphibians, and reptiles. Insome embodiments, the subject is livestock, such as cattle, swine,sheep, poultry, and horses, or pets, such as dogs and cats. The subjectcan be of any gender (i.e., male or female). The subject can also be anyage, such as elderly (generally, at least or above 60, 70, or 80 yearsof age), elderly-to-adult transition age subjects, adults,adult-to-pre-adult transition age subjects, and pre-adults, includingadolescents (e.g., 13 and up to 16, 17, 18, or 19 years of age),children (generally, under 13 or before the onset of puberty), andinfants. The subject can also be of any ethnic population or genotype.Some examples of human ethnic populations include Caucasians, Asians,Hispanics, Africans, African Americans, Native Americans, Semites, andPacific Islanders. The methods of the invention may be more appropriatefor some ethnic populations, such as Caucasians, especially northernEuropean populations, and Asian populations.

The cyclic oligosaccharide substance (i.e., active substance) beingadministered targets RPE cells. By “targeting” RPE cells is meant thatthe compound attaches to RPE cells by a covalent or non-covalentmechanism. In some embodiments, the compound is made to target RPE cellsby being administered directly at, into, or in the adjacent vicinity ofRPE cells, such as by injection or implantation. In other embodiments,the compound is made to target RPE cells by endowing the compound with atargeting agent that selectively targets RPE cells, and the compound maybe administered at, into, or in the adjacent vicinity of RPE cells, orremotely from the RPE cells (e.g., by systemic administration). Withoutbeing bound by theory, it is believed that the cyclic oligosaccharideforms a host-guest complex with A2E or other lipofuscin bisretinoid,with the cyclic oligosaccharide as the host and the A2E or otherlipofuscin bisretinoid as the guest molecule. The host-guest complex canbe considered an organized chemical entity resulting from theassociation of two or more components held together by non-covalentintermolecular forces.

The active substance used in the method described herein has acomposition having an active portion that includes one or more cyclicoligosaccharides. The cyclic oligosaccharide, as defined herein, is achemical moiety containing at least three monosaccharide units connecteddirectly or via one or more linkers to each other such that themonosaccharide units are arranged in a cyclic pattern that defines arelatively hydrophobic cavity capable of engaging in host-guest complexformation with A2E or related lipofuscin bisretinoid.

The number of monosaccharide units in the cyclic oligosaccharide can be,for example, four, five, six, seven, eight, nine, ten, and highernumbers (e.g., up to 12, 15, 18, or 20 units). The monosaccharide canbe, for example, an aldose or a ketose, and, in addition, either atriose, tetrose, pentose, hexose, or heptose. Typically, themonosaccharide considered herein contains at least four, five, six, orseven carbon atoms. Some specific examples of monosaccharides includeglucose, fructose, galactose, mannose, ribose, maltose, arabinose,xylose, erythrose, xylulose, and ribulose. In one embodiment, the cyclicoligosaccharide contains only one type of monosaccharide connected in acyclic pattern. In another embodiment, the cyclic oligosaccharidecontains more than one type of monosaccharide (e.g., two, three, ormore) connected in a cyclic pattern. The monosaccharide can be in a D-or L-configuration, although the D-configuration is more typical. Themonosaccharide units can be connected to each other by either an alphaor beta linkage, or a combination thereof, although an exclusive alphalinkage is more typical.

Examples of cyclic oligosaccharides suitable for use with the inventionare the cyclodextrins (α-D-glucopyranoses linked at the positions 1,4 byα-linkages), cyclomannins (α-D-mannopyranose units linked at thepositions 1,4 by α-linkages), the cyclogalactins (β-D-galactopyranoseunits linked at the 1,4 positions by β linkages) and the cycloaltrins(α-D-altropyranose units linked at the 1,4 positions by α linkages).Other examples of cyclic oligosaccharides are those having aheterogeneous monosaccharide composition, i.e., that contain acombination of two or more of the monosaccharides, such as any of thoseprovided above.

In one set of embodiments, at least one of the monosaccharide units isderivatized by containing a modified hydroxyl group in which thehydrogen atom of the hydroxyl group is replaced with a hydrocarbon groupor inorganic group. Some suitable types of hydrocarbon groups includethose containing at least one, two, three, four, five, or six carbonatoms, and which can be straight-chained or branched, saturated orunsaturated, and cyclic or acyclic. Some particular hydrocarbon groupsconsidered herein include methyl, ethyl, vinyl, n-propyl, allyl,isopropyl, cyclopropyl, n-butyl, sec-butyl, isobutyl, t-butyl,cyclobutyl, 3-butenyl, n-pentyl, isopentyl, neopentyl, cyclopentyl,cyclopentenyl, n-hexyl, isohexyl, cyclohexyl, phenyl, benzyl, naphthyl,anthracenyl, phenanthrenyl, tolyl, and xylyl groups. In one embodiment,the substituting hydrocarbon group contains only carbon and hydrogenatoms. In another embodiment, the substituting hydrocarbon groupincludes at least one heteroatom (e.g., at least one O, N, S, or halideatom, or combination thereof). Some examples of heteroatom-substitutedhydrocarbon groups include acyl groups (e.g., acetyl and propionylgroups), sulfonyl groups (e.g., methylsulfonyl and tosyl groups),alkyleneoxy groups (e.g., ethylenoxy groups), alkylenehydroxy groups(e.g., —CH₂CH₂CH₂OH or —CH₂CH₂(OH)CH₃), alkyleneamino groups (e.g.,—CH₂NH₂, —CH₂CH₂NH₂ or —CH₂CH₂CH₂NH₂ groups), alkylenethiol groups(e.g., —CH₂CH₂CH₂SH), amido groups (e.g., amide, N-methylamide, andN,N-dimethylamide groups), which link to the hydroxyl oxygen with theamido carbonyl to form a carbamate linkage, amino acids (e.g., aglycine, leucine, serine, or lysine group), dipeptides, oligopeptides,nucleobases (e.g., adenine, guanine, cytosine, thymine, and uracilgroups), nucleosides, nucleotides, saccharides (e.g., monosaccharides,disaccharides, and oligosaccharides), lectins, cofactors, andcombinations thereof, such as an alkyleneoxy-linked hydroxy, amino,amido, thiol, amino acid, peptide, or saccharide group. A substitutinginorganic group can be, for example, a phosphate, diphosphate,triphosphate, phosphate ester, sulfate, sulfonate, metal ion (e.g.,lithium, sodium, potassium, magnesium, or calcium ion), or aphosphate-monosaccharide group. Furthermore, the group can be neutral orcharged. The charged group can be cationic (e.g., an ammonium group,such as a quaternary ammonium group) or anionic (e.g., a carboxylategroup).

In other embodiments, at least one of the monosaccharide units can bederivatized by having one or more hydroxyl groups therein, themselves,replaced by any of the groups described above, or by other groups, suchas an N-bound amino, N-bound amido (e.g., N-bound amide or acetylamidegroup), or a thiol group. In yet other embodiments, at least one of themonosaccharide units can be derivatized by having one or more hydroxylgroups replaced with a hydrogen atom, thereby resulting in adeoxysaccharide unit.

By methods well-known in the art, several of the groups described above,particularly those containing one or more heteroatoms (e.g., amino,amido, ester, thiol, and aldehydic groups) can be used as reactivegroups for attaching the cyclic oligosaccharide to another chemicalentity, i.e., to a polysaccharide, another cyclic oligosaccharide, acell-targeting agent, a fluorophore, or other group, either directly orvia a linker to any other these groups. Any of the other chemicalentities considered as a part of the composition herein (e.g.,cell-targeting agent, fluorophore, or other group) can contain, or bederivatized to contain, any such reactive groups for the purpose ofattaching these groups to each other or to the cyclic oligosaccharide.

Particularly considered herein as cyclic oligosaccharides are thecyclodextrins. As is well-known in the art, cyclodextrins are typicallycomposed of five or more glucose (i.e., glucopyranoside) units connectedin a ring structure, linked as in amylose by alpha 1-4 (i.e.,alpha(1→4)) bonds. The cyclodextrins considered herein can convenientlybe represented by the following generic formula:

In generic formula (1) above, the R groups can be independently selectedfrom any of the groups described above, including hydrogen atom,hydrocarbon groups, heteroatom-substituted hydrocarbon groups, inorganicgroups, and biochemically-relevant groups. In some embodiments, all ofthe R groups in the formula are the same, while in other embodiments, atleast one of the R groups in the formula is chemically different fromother R groups. In further or alternative embodiments, one or more ofthe OR groups can be replaced by any of the groups described above. Insome embodiments, the cyclodextrin (or, more generally, cyclicoligosaccharide) is attached to a polysaccharide, wherein at least one(e.g., one, two, or three) of the R groups can represent either a directbond or a linker that bonds or links, respectively, the cyclodextrin(or, more generally, cyclic oligosaccharide) to the polysaccharide. Whengeneric formula (1) represents a cyclic oligosaccharide, the shownglucose groups can be generically replaced by one or a combination ofany of the monosaccharide groups described above. The subscript ndenotes the number of monosaccharide units, and can be any number above3, but more typically a number of 4, 5, 6, 7, 8, 9, or 10, or aparticular range therein. The arc shown in generic formula (1) denotes acyclic arrangement of monosaccharide units.

As a consequence of the chair conformation of the sugar units, allsecondary RO— groups (at C-2, C-3) are located on one side of the ring(large rim), while all the primary RO— groups at C-6 are situated towardthe exterior on the other side (large rim). As a result, the externalfaces are hydrophilic, making the cyclodextrins water-soluble. Incontrast, the internal portions (i.e., cavities) of the cyclodextrinsare much less hydrophilic (i.e., relatively hydrophobic), since theycontain the hydrogen of atoms C-3 and C-5, and ether groups.

The diameter of the internal cavity of the cyclic oligosaccharidedepends on the number of sugar (e.g., D-glucopyranose) units itcontains. The average interior diameters for α-, β- and γcyclodextrinsare typically about 0.66, 0.70, and 0.86 nm, respectively.

Some particular cyclodextrin structures are shown in the followingsub-generic formulas:

In formulas (2), (3), and (4), R is as defined above for generic formula(1). Furthermore, any of formulas (2), (3), and (4) can genericallyrepresent any cyclic oligosaccharide with the indicated number of sugarunits, by replacing one or more of the shown glucose groups with one ora combination of any of the monosaccharide groups described above.

The physico-chemical properties of the cyclodextrin derivatives dependstrongly on the kind and the degree of substitution. For example, theirsolubility in water ranges from insoluble, i.e., fortriacetyl-beta-cyclodextrin, to 147% soluble (w/v), i.e., forG-2-beta-cyclodextrin. In addition, cyclodextrins can be soluble indifferent types of organic solvents. For purposes of the instantinvention, the cyclic oligosaccharide or dimeric, trimer, highermultimeric, or polymeric form thereof is preferably substantially orcompletely soluble in water (i.e., at least 50%, 60%, 70%, 80%, 90%, or100% w/v).

The synthesis of cyclic oligosaccharides is well known in the art, andnumerous types are commercially available. Chemical modification ofcyclodextrins can be made directly on the native (alpha, beta, gamma)cyclodextrin rings by reacting a chemical reagent (nucleophiles orelectrophiles) with a properly functionalised cyclodextrin (Adair-Kirk,T. L., et al., Nat. Med., 14(10): pp. 1024-5, 2008; Khan, A. R., et al.,Chem. Rev., 98(5): pp. 1977-1996, 1998). To date, more than 1,500cyclodextrin derivatives have been made by chemical modification ofnative cyclodextrins. Cyclodextrins can also be prepared by de novosynthesis, starting with glucopyranose-linked oligopyranosides. Such asynthesis can be accomplished by using various chemical reagents orbiological enzymes, such as cyclodextrin transglycosylase. An overviewof chemically modified cyclodextrins as drug carriers in drug deliverysystems is described, for example, in Stella, V. J., et al., Toxicol.Pathol., 36(1): pp. 30-42, 2008, the disclosure of which is hereinincorporated by reference in its entirety. U.S. Pat. Nos. 3,453,259 and3,459,731 describe electroneutral cyclodextrins, the disclosures ofwhich are herein incorporated by reference in its entirety. Otherderivatives include cyclodextrins with cationic properties, as disclosedin U.S. Pat. No. 3,453,257; insoluble crosslinked cyclodextrins, asdisclosed in U.S. Pat. No. 3,420,788; and cyclodextrins with anionicproperties, as disclosed in U.S. Pat. No. 3,426,011, the disclosures ofwhich are all hereby incorporated by reference in their entirety. Amongthe cyclodextrin derivatives with anionic properties, carboxylic acids,phosphorous acids, phosphinous acids, phosphonic acids, phosphoricacids, thiophosphonic acids, thiosulphinic acids, and sulfonic acidshave been appended to the parent cyclodextrin, as disclosed, forexample, in U.S. Pat. No. 3,426,011, supra. Sulfoalkyl ethercyclodextrin derivatives have also been described, e.g., in U.S. Pat.No. 5,134,127, the disclosure of which is hereby incorporated byreference in its entirety. In some embodiments, the cyclicoligosaccharide can have two or more of the monosaccharide unitsreplaced by triazole rings, which can be synthetized by the Azide-alkyneHuisgen cycloaddition reaction (Bodine, K. D., et al., J. Am. Chem.Soc., 126(6): pp. 1638-9, 2004).

Although the cyclic oligosaccharide can be used in monomeric form, insome embodiments, dimerization, trimerization, or highermultimerization, or even polymerization, increases their ability to formmore stable complexes with A2E, as shown, for example, in FIG. 10.Typically, dimeric, trimeric, and higher multimeric cyclicoligosaccharides contain linkers that function as bridges between cyclicoligosaccharide units, as shown, for example, in FIG. 8D.

In some embodiments, at least two or more cyclic oligosaccharides arebound to each other (i.e., interconnected) via one or more linkers.Methods for functionalizing a cyclic oligosaccharide with a linkinggroup are well-known in the art. Reference is made, for example, to (a)Mocanu G. et al., “Cyclodextrin polymers,” J. Bioact. Compat. Pol.,2001; 16:315-342; (b) Liu Y., et al., “Cooperative binding and multiplerecognition by bridged bis(b-cyclodextrin)s with functional linkers”,Acc. Chem. Res., 2006; 39:681-691; (c) Ozmen E. Y., et al., “Synthesisand characterization of cyclodextrin-based polymers as a support forimmobilization of Candida rugosa lipase,” J. Mol. Catal. B-Enzym., 2009;57:109-114; (d) Trotta F. et al., “Characterization and applications ofnew hyper-cross-linked cyclodextrins,” Compos. Interface, 2009;16:39-48, the disclosures of which are herein incorporated by referencein their entirety. For example, a linker group containing a portionreactive to a hydroxyl group (e.g., a carboxyl group, preferablyactivated by a carbodiimide) can be reacted with the cyclodextrin toform a covalent bond thereto. Alternatively, one or more hydroxyl groupsof the cyclodextrin can be activated by known methods (e.g., tosylation)to react with a reactive group (e.g., amino group) on the linker.

Since the linker attaches at least two chemical entities to each other,the linker generally contains two reactive portions made to react andbond with each chemical entity. In one embodiment, a double-reactivelinker is first attached to a cyclic oligosaccharide (e.g.,cyclodextrin) to produce a linker-cyclodextrin compound that isisolated, and then the remaining reactive portion of the linker in thelinker-cyclodextrin compound is subsequently reacted with a secondlinker or molecule (e.g., a second cyclodextrin or a polysaccharide). Inthe foregoing embodiment, the second reactive portion of the linker isgenerally protected during reaction of the first reactive group, oralternatively, protection is not necessary in an embodiment where thefirst and second reactive portions of the linker react with the twomolecules differently. Particularly by the latter embodiment, adouble-reactive linker may be reacted with both molecules simultaneouslyto link them together. In other embodiments, the linker can haveadditional reactive groups in order to link to other molecules, such asanother cyclodextrin unit, polysaccharide, or a cell-targeting orfluorophore.

Numerous double-reactive linkers are known in the art. Such linkers canbe used for linking any of a variety of groups together when the groupspossess, or have been functionalized to possess, groups that can reactand link with the reactive linker. Some groups capable of reacting withdouble-reactive linkers include amino, thiol, hydroxyl, carboxyl, ester,and alkyl halide groups. For example, amino-amino coupling reagents canbe employed to link a cyclic oligosaccharide with a polysaccharide (or,for example, any of these groups with a fluorophore or with each other)when each of the groups to be linked possess at least one amino group.Some examples of amino-amino coupling reagents include diisocyanates,alkyl dihalides, dialdehydes, disuccinimidyl suberate (DSS),disuccinimidyl tartrate (DST), and disulfosuccinimidyl tartrate(sulfo-DST), all of which are commercially available. In otherembodiments, amino-thiol coupling agents can be employed to link a thiolgroup of one molecule with an amino group of another molecule. Someexamples of amino-thiol coupling reagents include succinimidyl4-(N-maleimidomethyl)-cyclohexane-1-carboxylate (SMCC), andsulfosuccinimidyl 4-(N-maleimidomethyl)-cyclohexane-1-carboxylate(sulfo-SMCC). In yet other embodiments, thiol-thiol coupling agents canbe employed to link groups bearing at least one thiol group.

In some embodiments, one or more linkers attach together two or morecyclic oligosaccharides, and one or more other linkers attach acell-targeting agent with one or more of the cyclic oligosaccharides. Inother embodiments, a linker that attaches cyclic oligosaccharides witheach other also links at least one of the cyclic oligosaccharides with acell-targeting agent. In further embodiments to any of the foregoingembodiments, a separate linker may be employed to link a fluorophore orother functional group with a cyclic oligosaccharide, or alternatively,any of the linkers described above may also be covalently attached to afluorophore or other functional entity. The other functional entity canbe, for example, a drug or prodrug that would be hydrolyzed and/orotherwise released upon reaching the targeted cell. In some embodiments,such a drug or prodrug is excluded from the cyclic oligosaccharide. Inany of the exemplary embodiments provided above, the linker may inaddition or alternatively link a cyclic oligosaccharide to apolysaccharide unit, and/or link a targeting agent, fluorophore, orother functional entity to a polysaccharide unit that functions as apendant group or linker in a cyclic oligosaccharide.

In some embodiments, the linker is as small as a single atom (e.g., an—O—, —CH₂—, or —NH— linkage), or two or three atoms in length (e.g., anamido, ureido, carbamato, ester, carbonate, sulfone, ethylene, ortrimethylene linkage). In other embodiments, the linker provides morefreedom of movement by being at least four, five, six, seven, or eightatom lengths, and up to, for example, 10, 12, 14, 16, 18, 20, 22, 24,26, 28, or 30 atom lengths.

In one embodiment, the linker is a hydrocarbon linker, e.g., as derivedfrom any of the hydrocarbon groups described above by removal of two ormore hydrogen atoms therefrom (thus resulting in two or more linkingbonds therein). Some examples of hydrocarbon linkers include methylene(—CH₂—), ethylene (—CH₂CH₂—), trimethylene (—CH₂CH₂CH₂—),tetramethylene, pentamethylene, hexamethylene, o-, m-, and p-phenylene,and vinylene.

The hydrocarbon linker may or may not also include heteroatoms.Furthermore, the heteroatoms may or may not be linking atoms. In aparticular embodiment, the hydrocarbon linker contains one, two, three,or more amino groups. Some examples of amino-containing linkers include1,2-ethylenediamine, 1,3-trimethylenediamine, 1,4-tetramethylenediamine,1,5-pentamethylenediamine, 1,6-hexamethylenediamine, diethylenetriamine,triethylenetetramine, and diaminobenzene linkers. In another particularembodiment, the hydrocarbon linker contains one, two, three, or moreoxygen-linking (i.e., —O—) atoms or hydroxy groups. Some examples ofsuch linkers include ethylene glycol, diethylene glycol, triethyleneglycol, 2-hydroxypropane, 2,3-dihydroxybutane, dihydroxybenzene, and thepolyethylene glycol (i.e., PEG) linkers. In other particularembodiments, the linkers include one, two, three, or more carbonylgroups. Some examples of such linkers include methyl dicarbonyl,ethylene-1,2-dicarbonyl, propylene-1,3-dicarbonyl, and the like.

The linker can also be or include a biological group, such as, forexample, a nucleobase, nucleoside, nucleotide, dinucleotide,trinucleotide, tetranucleotide, a higher oligonucleotide, amino acid,dipeptide, tripeptide, tetrapeptide, pentapeptide, hexapeptide, a higheroligopeptide, saccharide, disaccharide, trisaccharide, tetrasaccharide,a higher oligosaccharide, lipid, or fatty acid.

In particular embodiments, the linker is a rigid linker. A rigid linkermay be beneficial in some embodiments by reducing the degree of freedomof a linked molecule, or forcing at least two linked groups to remain atfixed distances from each other or from another molecule. Some examplesof rigid linkers are those containing aromatic or heteroaromatic rings,such as linkers that include benzene, naphthalene, styrene,divinylbenzene, biphenyl, triphenyl, or other aromatic rings orpolycyclic ring systems.

In a particular set of embodiments, the linker has a structurerepresented by the following generic formula:

In formula (5) above, subscripts r, s, and t can independently be 0 oran integer of at least 1, provided that at least one of r, s, and t isnot 0. Generally, each end of the linker generally also includes aheteroatom-containing group through which a covalent bond is formedbetween the linker and groups that are linked. As discussed earlier,such heteroatom-containing groups include, for example, oxo (—O—), amino(e.g., —NH—, or —N(CH₃)—), amido (e.g., —C(O)NH— or —C(O)N(CH₃)—),ester, ureido, carbonato, sulfanoto, and phosphonato groups. Indifferent embodiments, r, s, and t are independently selected from 0, oran integer of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16,or selected to be within a range therein, provided that at least one ofr, s, and t is not 0. In one set of embodiments, r and t are 0, and srepresents any of the foregoing non-zero numbers or possible rangestherein. In another set of embodiments, r is 0, while s and tindependently represent any of the foregoing non-zero numbers orpossible ranges therein. In another set of embodiments, s is zero whileat least one of r and t represents any of the foregoing non-zero numbersor possible ranges (thereby resulting in an alkylene structure forformula 5). In another set of embodiments, r, s, and t independentlyrepresent any of the foregoing non-zero numbers or possible rangestherein. In particular embodiments, r and t are independently 1, 2, 3,or 4, or a subset therein, while s is selected from any of the foregoingnon-zero numbers or possible ranges therein.

In some embodiments, the linker is a polysaccharide. As defined herein,a polysaccharide is a chemical moiety containing a multiplicity (e.g.,at least 10, and more typically at least 100) of monosaccharide unitsconnected to each other in a linear and/or branched (i.e., non-cyclic)arrangement. In one embodiment, the polysaccharide is ahomopolysaccharide by having all of the monosaccharide units as the sametype (e.g., all glucose units). In another embodiment, thepolysaccharide is a heteropolysaccharide by having different types ofmonosaccharide units. The polysaccharide considered herein possesses,for example, at least 10, 20, 50, 100, 200, 500, 1000, 5000, 10000,50000, 100000, 150000, 200000, or higher number of units, oralternatively, molecular weights (or average molecular weights) of atleast 100, 200, 500, 1000, 5000, 10000, 20000, 30000, 40000, 50000,60000, 70000, 80000, 90000, 100000, 150000, 200000, or 500000 Daltons(Da), or the polysaccharide possesses a number of units or molecularweight within a range bounded by any of the foregoing exemplary values.One or more of the monosaccharide units of the polysaccharide can bederivatized in the same manner as described above for the cyclicoligosaccharide. In a particular embodiment, the polysaccharide isfunctionalized with one, two, three, or higher multiplicity of aminogroups. Such a polysaccharide is denoted herein as an “aminopolysaccharide”.

Particularly considered herein as linkers are those polysaccharidesconstructed solely of glucose units (i.e., a glucan polysaccharide). Theglucan polysaccharide can be an alpha-glucan or beta-glucanpolysaccharide, although the glucan polysaccharide is more commonly analpha-glucan polysaccharide. A particular class of alpha-glucanpolysaccharide considered herein is dextran. As known in the art, adextran generally consists predominantly of glucose molecules linkedpredominantly or exclusively by alpha-1,6-glycosidic linkages. Dependingon the type of dextran used, the dextran can contain any of a broadrange of branching. The branching generally results from alpha-1,4glycosidic linkages, and in some cases, alpha-1,2 and alpha-1,3glycosidic linkages. Other types of alpha-glucan polysaccharideconsidered herein are the starches (e.g., amylose and amylopectin),glycogen, and pullulan. Some particular classes of beta-glucanpolysaccharides considered herein include cellulose, hemicellulose,cellodextrin, chrysolaminarin, lentinan, and zymosan. In someembodiments, at least a portion of the glucose units can be derivatized,such as found in chitin (i.e., a polymer of N-acetylglucosamine). Otherderivatized glycans include the glycosaminoglycans, such as chondroitinsulfate, dermatan sulfate, heparin, heparan sulfate, hyaluronic acid,and keratan sulfate.

Other classes of polysaccharides considered herein are the fructans andgalactans. Some examples of fructans include the inulins,fructooligosaccharides, and Levan polysaccharide (a homopolysaccharideof fructose with varying degrees of branching). An example of a galactanis the class of galactooligosaccharides.

A particular example of a heteropolysaccharide considered herein is theclass of arabinoxylans, which are copolymers of arabinose and xylose.Another heteropolysaccharide considered herein is agarose.

In one set of embodiments, the polysaccharide consists solely ofmonosaccharide units. In another set of embodiments, the polysaccharidecan also include a non-saccharide moiety. For example, thepolysaccharide can be a glycoprotein or proteoglycan by containing aproteinaceous component, or the polysaccharide can be alipopolysaccharide by containing a lipid component.

In some embodiments, the cyclic oligosaccharide (or a dimeric, trimeric,multimeric, or polymeric form thereof) is covalently bound to one ormore polysaccharide units. The polysaccharide units may be attached tothe cyclic oligosaccharide as a pendant group (i.e., non-linker) or as alinker. In different embodiments, at least one, two, three, four, five,six, and up to, for example, 10, 15, 20, or 30 cyclic oligosaccharidesare bound to a polysaccharide unit. The cyclic oligosaccharide can bedirectly bound or linked via a linker to the polysaccharide by any oneor more suitable atoms present on the cyclic oligosaccharide. Forexample, in different embodiments, the cyclic oligosaccharide can bebound to the polysaccharide by one or more of the carbon atoms of thecyclic oligosaccharide, e.g., by replacement of one of the hydroxylgroups of the cyclic oligosaccharide by a binding atom of thepolysaccharide or by a binding atom of a linker group linked to thepolysaccharide. Alternatively, the cyclic oligosaccharide can be boundto the polysaccharide by one or more of its hydroxyl groups (i.e.,oxygen atoms), or the cyclic oligosaccharide can be bound to thepolysaccharide by one or more heteroatom-containing groups present onthe cyclic oligosaccharide. In the same manner, the polysaccharide canbe directly bound or linked via a linker to the cyclic oligosaccharideby any one or more suitable atoms present on the polysaccharide.

In particular embodiments, at least one cell-targeting agent is attachedto the cyclic oligosaccharide, either as an integral moiety of thecyclic oligosaccharide, or bound directly to the cyclic oligosaccharideor indirectly via a linker. In one set of embodiments, thecell-targeting agent is embedded within the structure of the cyclicoligosaccharide, e.g., as cyclomannins or cyclic oligosaccharidescontaining one or more mannoses with phosphate groups introduced atposition 6 of mannose rings. A generalized structure depicting theforegoing embodiment is provided by the following representation:

In the above representation, C represents a cyclic oligosaccharide. Inparticular embodiments, at least one of X₁ represents a cell-targetingagent, such as M6P. Each of X₁ can also represent a multiplicity (e.g.,two, three, or more) of any of the foregoing groups. The dashed line toX₁ indicates that these groups may or may not be present, and, ifpresent, may be attached to any portion of the group to which they arebound. The representation in formula (6) is meant to be non-limiting bydepicting a minimum set of features that can be expanded upon innumerous ways. For example, additional embedded cyclic oligosaccharidesmay be included, or additional C or other groups (e.g., one or morependant or linking polysaccharide groups) may be bound to C.

In another set of embodiments, two cyclic oligosaccharides (C) areconnected by a linker (L). A generalized structure depicting theforegoing embodiment is provided by the following representation:

In the above representation, each C may be identical or different. Inparticular embodiments, at least one of X₁, X₂, and X₃ represents acell-targeting agent. One or more of X₁, X₂, and X₃ can alternatively,or in addition (i.e., optionally) represent a fluorophore, or otherfunctional moiety. Each of X₁, X₂, and X₃ can also represent amultiplicity (e.g., two, three, or more) of any of the foregoing groups.The dashed lines to each of X₁, X₂, and X₃ indicate that these groupsmay or may not be present, and, if present, may be attached to anyportion of the group to which they are bound. The continuous linebetween L and C represents at least one direct bond. The representationin formula (7) is meant to be non-limiting by depicting a minimum set offeatures that can be expanded upon in numerous ways. For example, anadditional P group may be bound to X₂ and/or X₃, or an additional Cgroup may be bound to X₁, X₂, and/or X₃.

In another set of embodiments, two cyclic oligosaccharides rings arependant to at least one (L) linker chain. A generalized structuredepicting the foregoing embodiment is provided by the followingrepresentation:

The above representation corresponds to a subset of dimers of cyclicoligosaccharide rings defined above. C may represent more than one typeof cyclic oligosaccharides bound to each other either directly or viaone or more linkers L₁, L₂. L₁ represents one or more linkers of one ormore than one type. L₂ represents none or one linker. L₁ and L₂ can bethe same or different. In particular embodiments, X represents acell-targeting agent as defined above. One or more of X can be presentin the cyclic oligomer and/or in the linker. Alternatively, or inaddition (i.e., optionally) X represents a fluorophore, or otherfunctional moiety. In this embodiment, X is not considered as another Lgroup. Each of X can also represent a multiplicity (e.g., two, three, ormore) of any of the foregoing groups. The dashed lines to each Xindicate that these groups may or may not be present, and, if present,may be attached to any portion of the group to which they are bound. Thecontact between L and C represents at least one direct bond. Therepresentation in formula (8) is meant to be non-limiting by depicting aminimum set of features that can be expanded upon in numerous ways. Therepresentation in formula (8) is meant to be non-limiting by depicting aminimum set of features that can be expanded upon in numerous ways. Forexample, additional embedded cyclic oligosaccharides may be included, ormultiple L groups may be used to be bind C cyclic units.

In another set of embodiments, the active composition has an activeportion that includes three or more cyclic oligosaccharides (multimer).A generalized structure depicting the foregoing embodiment is providedin FIG. 3A. In FIG. 3A, C represents a cyclic oligosaccharide and Lrepresents a linker. In particular embodiments, at least one C containsattached or embedded cell-targeting sequences, such as Mannose-6-P, orin the case of mannose-containing cyclic oligosaccharides, a phosphategroup at position 6 of a mannose ring. Each of the solid linesconnecting C with L represents at least one direct bond or linker. Thedashed lines connecting C to L indicate that these links may or may notbe present, and, if present, may be attached to any portion of the groupto which they are bound. The representation in FIG. 3A is meant to benon-limiting by depicting a minimum set of features that can be expandedupon in numerous ways. For example, additional embedded cyclicoligosaccharides may be included, or multiple L groups may be used tolink two C units. The linker group (L) can be, for example, acryloyl,phenylacetylene, polyphenylene, or ethynylene poly(maleic anhydride)polyallylamine, poly(ethyleneimine) dendrimers, chitosane, and alginate.In a particular embodiment, FIG. 3A represents epichlorohydrin linearmultimers threaded on PEG (molecular tubes). The cyclic oligosaccharidemultimers can be synthesized by, for example: (1) radical polymerizationof monofunctional CD monomers, (2) polymer-analogous reaction ofpolymers with cyclic oligosaccharides, or (3) partial crosslinking ofcyclic oligosaccharides.

In another set of embodiments, the invention is directed to acomposition having an active portion therein that includes two or moredimers of cyclic oligosaccharide rings (multimer). Some generalizedstructures depicting the foregoing embodiments are provided in FIGS. 3Band 3C. Dimers can be identical or, alternatively, may be composed ofmore than one type of cyclic oligosaccharide. R may representstreptavidin, polymers or multimerizing agents that facilitate theorganization of dimers in tandems. For example, R can be dextran,acryloyl, phenylacetylene, polyphenylene, or ethynylene poly(maleicanhydride) polyallylamine, poly(ethyleneimine) dendrimers, chitosane,and alginate, epichlorohydrin linear chains threaded on PEG (moleculartubes). Multimers are generally synthesized from cyclic oligosaccharidesmonomers or dimers by one of the three methods (1) radicalpolymerization, (2) polymer-analogous reaction, or (3) by partialcrosslinking. In particular embodiments, the linker L2 may not bepresent and optionally L1 can be the same as R. The angle between dimerscan be any. However, in some embodiments, an approximate 101° angle ispreferred for it is believed to further increase the selectivecomplexation of A2E and related bisretinoids. The binding to R can occurvia one or both cyclic oligosaccharides (C), and/or through the linkerL1 or L2. The dashed lines indicate that these links may or may not bepresent, and, if present, may be attached to any portion of the group towhich they are bound. Additionally, X can be attached to C, L1, L2 andor R. X represents embedded cell-targeting sequences as described above.The representations in FIGS. 3B and 3C are meant to be non-limiting bydepicting a minimum set of features that can be expanded upon innumerous ways. For example, additional embedded cyclic oligosaccharidesmay be included, or multiple L groups may be used to bind C cyclicunits.

In some embodiments, any one or more of the above-described genericclasses or specific types of cyclic oligosaccharides is excluded fromthe method of treatment described herein. For example, in someembodiments, cyclic oligosaccharides containing six or less ring sugarunits, such as the alpha-cyclodextrins, are excluded. In otherembodiments, monomethylated, dimethylated, trimethylated, orhydroxyalkylated (e.g., 2-hydroxyethylated, 2-hydroxypropylated, or3-hydroxypropylated) cyclic oligosaccharides (e.g., cyclodextrins) areexcluded. In other embodiments, charged (e.g., positively- ornegatively-charged) cyclic oligosaccharides (e.g., cyclodextrins) areexcluded, while in other embodiments, such charged cyclicoligosaccharides are included. In more specific embodiments, one or moreof the following cyclodextrins may be excluded:trimethyl-beta-cyclodextrin, 2-hydroxyethyl-beta-cyclodextrin,2-hydroxypropyl-beta-cyclodextrin, 3-hydroxypropyl-beta-cyclodextrin,and beta-cyclodextrin sulfobutylether sodium or potassium salt.

The cell-targeting agent (i.e., “targeting agent”) is any chemicalentity that has the ability to bind to (i.e., “target”) a RPE cell. Thecell-targeting agent may target any part of the RPE cell, e.g., cellmembrane, organelle (e.g., lysosome or endosome), or cytoplasmicmolecule. In one embodiment, the cell-targeting agent targets acomponent of a RPE cell in a selective manner. By selectively targetinga component of an RPE cell, the cell-targeting agent can, for example,selectively target certain components of cells over other types ofcellular components. In other embodiments, the targeting agent targetscellular components non-selectively, e.g., by targeting cellularcomponents found in most or all cells.

In various embodiments, the targeting agent can be, or include, forexample, a peptide, dipeptide, tripeptide (e.g., glutathione),tetrapeptide, pentapeptide, hexapeptide, higher oligopeptide, protein,monosaccharide, disaccharide, trisaccharide, tetrasaccharide, higheroligosaccharide, polysaccharide (e.g., a carbohydrate), nucleobase,nucleoside (e.g., adenosine, cytidine, uridine, guanosine, thymidine,inosine, and S-Adenosyl methionine), nucleotide (i.e., mono-, di-, ortri-phosphate forms), dinucleotide, trinucleotide, tetranucleotide,higher oligonucleotide, nucleic acid, cofactor (e.g., TPP, FAD, NAD,coenzyme A, biotin, lipoamide, metal ions (e.g., Mg2+), metal-containingclusters (e.g., the iron-sulfur clusters), or a non-biological (i.e.,synthetic) targeting group. Some particular types of proteins includeenzymes, hormones, antibodies (e.g., monoclonal antibodies), lectins,and steroids.

Antibodies for use as targeting molecules are generally specific for oneor more cell surface antigens. In a particular embodiment, the antigenis a receptor. The antibody can be a whole antibody, or alternatively, afragment of an antibody that retains the recognition portion (i.e.,hypervariable region) of the antibody. Some examples of antibodyfragments include Fab, Fc, and F(ab′)₂. In particular embodiments,particularly for the purpose of facilitating crosslinking of theantibody to the composition described herein, the antibody or antibodyfragment can be chemically reduced to derivatize the antibody orantibody fragment with sulfhydryl groups.

In particular embodiments, the targeting agent is a ligand of aninternalized receptor of the target cell. For example, the targetingagent can be a targeting signal for acid hydrolase precursor proteinsthat transport various materials to lysosomes. One such targeting agentof particular interest is mannose-6-phosphate (M6P), which is recognizedby mannose 6-phosphate receptor (MPR) proteins in the trans-Golgi.Endosomes are known to be involved in transporting M6P-labeledsubstances to lysosomes.

In another embodiment, the targeting molecule is a peptide containing anRGD sequence, or variants thereof, that bind RGD receptors on thesurface of many types of cells. Other ligands include, for example,transferrin, insulin, amylin, and the like. Receptor internalization ispreferred to facilitate intracellular delivery of the inventivecomposition described herein.

In one set of embodiments, one cell-targeting molecule or group, orseveral (e.g., two, three, or more) of the same type of cell-targetingmolecule or group are attached to the cyclic oligosaccharide or on alinker or pendant group thereon. In other embodiments, two or moredifferent types of targeting molecules are attached to the cyclicoligosaccharide or on a linker or pendant group thereon. At least onepossible advantage in using several cell-targeting molecules is thatuptake of the cyclic oligosaccharide into RPE cells may be increasedrelative to use of a single cell-targeting molecule.

In some embodiments, a fluorophore may be attached to the cyclicoligosaccharide composition described above. Incorporation of one ormore fluorophores can have several purposes. In some embodiments, one ormore fluorophores are included in order to quantify cellular uptake andretention of the cyclic oligosaccharide composition (e.g., by afluorescence spectroscopic method).

As used herein, a “fluorophore” refers to any species with the abilityto fluoresce (i.e., that possesses a fluorescent property). For example,in one embodiment, the fluorophore is an organic fluorophore. Theorganic fluorophore can be, for example, a charged (i.e., ionic)molecule (e.g., sulfonate or ammonium groups), uncharged (i.e., neutral)molecule, saturated molecule, unsaturated molecule, cyclic molecule,bicyclic molecule, tricyclic molecule, polycyclic molecule, acyclicmolecule, aromatic molecule, and/or heterocyclic molecule (i.e., bybeing ring-substituted by one or more heteroatoms selected from, forexample, nitrogen, oxygen and sulfur). In the particular case ofunsaturated fluorophores, the fluorophore contains one, two, three, ormore carbon-carbon and/or carbon-nitrogen double and/or triple bonds. Ina particular embodiment, the fluorophore contains at least two (e.g.,two, three, four, five, or more) conjugated double bonds aside from anyaromatic group that may be in the fluorophore. In other embodiments, thefluorophore is a fused polycyclic aromatic hydrocarbon (PAH) containingat least two, three, four, five, or six rings (e.g., naphthalene,pyrene, anthracene, chrysene, triphenylene, tetracene, azulene, andphenanthrene) wherein the PAH can be optionally ring-substituted orderivatized by one, two, three or more heteroatoms orheteroatom-containing groups.

In other embodiments, the organic fluorophore is a xanthene derivative(e.g., fluorescein, rhodamine, Oregon green, eosin, and Texas Red),cyanine or its derivatives or subclasses (e.g., streptocyanines,hemicyanines, closed chain cyanines, phycocyanins, allophycocyanins,indocarbocyanines, oxacarbocyanines, thiacarbocyanines, merocyanins, andphthalocyanines), naphthalene derivatives (e.g., dansyl and prodanderivatives), coumarin and its derivatives, oxadiazole and itsderivatives (e.g., pyridyloxazoles, nitrobenzoxadiazoles, andbenzoxadiazoles), pyrene and its derivatives, oxazine and itsderivatives (e.g., Nile Red, Nile Blue, and cresyl violet), acridinederivatives (e.g., proflavin, acridine orange, and acridine yellow),arylmethine derivatives (e.g., auramine, crystal violet, and malachitegreen), and tetrapyrrole derivatives (e.g., porphyrins and bilirubins).Some particular families of dyes considered herein are the Cy® family ofdyes, the Alexa® family of dyes, the ATTO® family of dyes, and the Dy®family of dyes. The ATTO® dyes, in particular, can have severalstructural motifs, including, coumarin-based, rhodamine-based,carbopyronin-based, and oxazine-based structural motifs.

The fluorophore can be attached to the active portion (e.g., to thecyclic oligosaccharide, polysaccharide pendant group, a linker, or othergroup) by any of the linking methodologies known in the art. Forexample, a commercial mono-reactive fluorophore (e.g., NHS-Cy5) orbis-reactive fluorophore (e.g., bis-NHS-Cy5 or bis-maleimide-Cy5) can beused to link the fluorophore to one or more molecules containingappropriate reactive groups (e.g., amino, thiol, hydroxy, aldehydic, orketonic groups). Alternatively, the active portion of the inventivecomposition can be derivatized with one, two, or more such reactivegroups, and these reactive portions reacted with a fluorophorecontaining appropriate reactive groups (e.g., an amino-containingfluorophore).

In the method of treatment described herein, the hydrophobic (binding)cavity of the cyclic oligosaccharide must be available to complex A2E orother lipofuscin bisretinoid lipid when the cyclic oligosaccharidereaches the RPE cells. Preferably, in order to ensure this, the cyclicoligosaccharide is not complexed with a guest molecule whenadministered, i.e., the cyclic oligosaccharide possesses an emptyhydrophobic cavity, and is thereby not functioning as a carrier whenadministered. In preferred embodiments, the cyclic oligosaccharide isdevoid of a lipophilic compound functioning as a guest, particularlythose that covalently react with RAL, or more preferably, the cyclicoligosaccharide is devoid of any guest compound altogether.

The cyclic oligosaccharide can be administered by any route that permitsthe cyclic oligosaccharide to contact RPE cells. The administration canbe, for example, ocular, parenteral (e.g., subcutaneous, intramuscular,or intravenous), topical, transdermal, intravitreous, retro-orbital,subretinal, subscleral, oral, sublingual, or buccal modes ofadministration. Some of the foregoing exemplary modes of administrationcan be achieved by injection. However, in some embodiments, injection isavoided by use of a slow-release implant in the vicinity of the retina(e.g., subscleral route) or by administering drops to the conjuctiva.

The cyclic oligosaccharide is administered in atherapeutically-effective amount (i.e., therapeutically-effectivedosage). The term “therapeutically-effective amount” or“therapeutically-effective dosage,” as used herein, corresponds to anamount of active agent effective for providing any of the desiredtherapeutic effects described above, preferably without a substantialtoxic effect to the subject.

In some embodiments, the active compound is administered, at leastinitially, at levels lower than that required in order to achieve adesired therapeutic effect, and the dose gradually or suddenly increaseduntil a desired effect is achieved. In other embodiments, the activecompound is administered, at least initially, at levels higher than thatrequired in order to accelerate a desired therapeutic effect, and thedose gradually or suddenly moderated until a desired effect is achieved.

The selected dosage level will depend upon several factors, asdetermined by a medical practitioner. Some of these factors include thetype of disease or condition being treated, the stage or severity of thecondition or disease, the efficacy of the active compound being used andits bioavailability profile, as well as the specifics (e.g., genotypeand phenotype) of the subject being treated, e.g., age, sex, weight, andoverall condition.

Particularly for systemic modes of administration, the dosage can be,for example, in the range of about 0.01, 0.1, 0.5, 1, 5, or 10 mg per kgof body weight per day to about 20, 50, 100, 500, or 1000 mg perkilogram of body weight per day, or bi-daily, or twice, three, four, ormore times a day. Particularly in embodiments where the active substanceis administered non-systemically directly at the retina, the dosage candisregard body weight, and can be in smaller amounts (e.g., 1-1000 μgper dose). In some embodiments, the daily dose of the active compound isthe lowest dose effective to produce a therapeutic effect. In someembodiments, the active compound is not administered in discretedosages, but in a continuous mode, such as provided by a slow releaseimplant or intravenous line.

Typically, in order for the cyclic oligosaccharide to be administratableto a subject, the cyclic oligosaccharide is formulated together with oneor more pharmaceutically acceptable carriers (additives) and/ordiluents, as well known in the art of pharmaceutical compositions. Thepharmaceutical compositions of the present invention may be speciallyformulated for administration in solid or liquid form, including thoseadapted for the following: (1) oral administration, for example,drenches (aqueous or non-aqueous solutions or suspensions), tablets,e.g., those targeted for buccal, sublingual, and systemic absorption,boluses, powders, granules, pastes for application to the tongue; (2)parenteral administration, for example, by subcutaneous, intramuscular,intravenous or epidural injection as, for example, a sterile solution orsuspension, or sustained-release formulation; (3) topical application,for example, as a cream, ointment, or a controlled-release patch orspray applied to the skin; (4) sublingually; (5) ocularly; (6)transdermally; or (7) nasally.

The phrase “pharmaceutically acceptable” is used herein to refer tothose compounds, materials, compositions, and/or dosage forms that are,within the scope of sound medical judgment, suitable for entering aliving organism or living biological tissue, preferably withoutsignificant toxicity, irritation, or allergic response.

The phrase “pharmaceutically-acceptable carrier,” as used herein,generally refers to a pharmaceutically-acceptable composition, such as aliquid or solid filler, diluent, excipient, manufacturing aid (e.g.,lubricant, talc magnesium, calcium or zinc stearate, or steric acid), orsolvent encapsulating material, useful for introducing the active agentinto the body. Each carrier must be “acceptable” in the sense of beingcompatible with other ingredients of the formulation and not injuriousto the patient. Examples of suitable aqueous and non-aqueous carriersthat may be employed in the pharmaceutical compositions of the inventioninclude, for example, water, ethanol, polyols (such as glycerol,propylene glycol, polyethylene glycol, and the like), vegetable oils(such as olive oil), and injectable organic esters (such as ethyloleate), and suitable mixtures thereof. Proper fluidity can bemaintained, for example, by the use of coating materials, such aslecithin, by the maintenance of the required particle size in the caseof dispersions, and by the use of surfactants.

Other examples of materials that can serve aspharmaceutically-acceptable carriers include: (1) sugars, such aslactose, glucose and sucrose; (2) starches, such as corn starch andpotato starch; (3) cellulose, and its derivatives, such as sodiumcarboxymethyl cellulose, ethyl cellulose and cellulose acetate; (4)powdered tragacanth; (5) malt; (6) gelatin; (7) talc; (8) excipients,such as cocoa butter and suppository waxes; (9) oils, such as peanutoil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil andsoybean oil; (10) glycols, such as propylene glycol; (11) polyols, suchas glycerin, sorbitol, mannitol and polyethylene glycol; (12) esters,such as ethyl oleate and ethyl laurate; (13) agar; (14) bufferingagents, such as magnesium hydroxide and aluminum hydroxide; (15) alginicacid; (16) pyrogen-free water; (17) isotonic saline; (18) Ringer'ssolution; (19) ethyl alcohol; (20) pH buffered solutions; (21)polyesters, polycarbonates and/or polyanhydrides; and (22) othernon-toxic compatible substances employed in pharmaceutical formulations.

The active agent can also be in the form of apharmaceutically-acceptable salt. The term “pharmaceutically-acceptablesalt,” as used herein, refers to the relatively non-toxic, inorganic ororganic addition salts of compounds of the present invention.

In one embodiment, the active agent may contain one or more basicfunctional groups, such as amino or alkylamino, and thereby, can formpharmaceutically-acceptable salts by reaction with apharmaceutically-acceptable acid. These salts can be prepared in situ inthe administration vehicle or the dosage form manufacturing process, orby separately reacting a purified compound of the invention in its freebase form with a suitable organic or inorganic acid, and isolating thesalt thus formed during subsequent purification. Some representativesalts include those generated by reaction of the free base withhydrobromic, hydrochloric, sulfuric, sulfamic, bisulfuric, phosphoric,nitric, acetic, propionic, benzoic, 2-acetoxybenzoic, malic, glycolic,valeric, oleic, palmitic, stearic, lauric, benzoic, lactic,toluenesulfonic, methansulfonic, ethanedisulfonic, citric, ascorbic,maleic, oxalic, fumaric, phenylacetic, isothionic, succinic, tartaric,glutamic, salicylic, sulfanilic, napthylic, lactobionic, gluconic,laurylsulfonic acids, and the like. (Berge et al. (1977) “PharmaceuticalSalts”, J. Pharm. Sci. 66:1-19).

In another embodiment, the active agent may contain one or more acidicfunctional groups, and thereby, can form pharmaceutically-acceptablesalts by reaction with a pharmaceutically-acceptable base. These saltscan likewise be prepared in situ in the administration vehicle or thedosage form manufacturing process, or by separately reacting thepurified compound in its free acid form (e.g., hydroxyl or carboxyl)with a suitable base, and isolating the salt thus formed duringsubsequent purification. Some representative salts include thosegenerated by reaction of the free acid with a metal hydroxide, metalalkoxide, ammonium hydroxide, or an amine, such as ammonia or apharmaceutically-acceptable organic primary, secondary or tertiaryamine. Some representative alkali or alkaline earth salts includelithium, sodium, potassium, calcium, magnesium, and aluminum salts. Somerepresentative organic amines useful for the formation of base additionsalts include ethylamine, diethylamine, ethylenediamine, ethanolamine,diethanolamine, piperazine and the like. (See, for example, Berge etal., supra).

Various auxiliary agents, such as wetting agents, emulsifiers,lubricants (e.g., sodium lauryl sulfate and magnesium stearate),coloring agents, release agents, coating agents, sweetening agents,flavoring agents, preservative agents, and antioxidants can also beincluded in the pharmaceutical composition. Some examples ofpharmaceutically-acceptable antioxidants include: (1) water solubleantioxidants, such as ascorbic acid, cysteine hydrochloride, sodiumbisulfate, sodium metabisulfite, sodium sulfite, and the like; (2)oil-soluble antioxidants, such as ascorbyl palmitate, butylatedhydroxyanisole (BHA), butylated hydroxytoluene (BHT), lecithin, propylgallate, alpha-tocopherol, and the like; and (3) metal chelating agents,such as citric acid, ethylenediamine tetraacetic acid (EDTA), sorbitol,tartaric acid, phosphoric acid, and the like. In some embodiments, thepharmaceutical formulation includes an excipient selected from, forexample, celluloses, liposomes, micelle-forming agents (e.g., bileacids), and polymeric carriers, e.g., polyesters and polyanhydrides.Suspensions, in addition to the active compounds, may contain suspendingagents, such as, for example, ethoxylated isostearyl alcohols,polyoxyethylene sorbitol and sorbitan esters, microcrystallinecellulose, aluminum metahydroxide, bentonite, agar-agar and tragacanth,and mixtures thereof. Prevention of the action of microorganisms on theactive compounds may be ensured by the inclusion of variousantibacterial and antifungal agents, such as, for example, paraben,chlorobutanol, phenol sorbic acid, and the like. It may also bedesirable to include isotonic agents, such as sugars, sodium chloride,and the like into the compositions. In addition, prolonged absorption ofthe injectable pharmaceutical form may be brought about by the inclusionof agents that delay absorption, such as aluminum monostearate andgelatin.

Pharmaceutical formulations of the present invention may be prepared byany of the methods known in the pharmaceutical arts. The amount ofactive ingredient that can be combined with a carrier material toproduce a single dosage form will vary depending upon the host beingtreated and the particular mode of administration. The amount of activeingredient that can be combined with a carrier material to produce asingle dosage form will generally be that amount of the compound thatproduces a therapeutic effect. Generally, the amount of active compoundwill be in the range of about 0.1 to 99 percent, more typically, about 5to 70 percent, and more typically, about 10 to 30 percent.

Formulations of the invention suitable for oral administration may be inthe form of capsules, cachets, pills, tablets, lozenges (using aflavored basis, usually sucrose and acacia or tragacanth), powders,granules, or as a solution or a suspension in an aqueous or non-aqueousliquid, or as an oil-in-water or water-in-oil liquid emulsion, or as anelixir or syrup, or as pastilles (using an inert base, such as gelatinand glycerin, or sucrose and acacia) and/or as mouth washes and thelike, each containing a predetermined amount of a compound of thepresent invention as an active ingredient. The active compound may alsobe administered as a bolus, electuary, or paste.

Methods of preparing these formulations or compositions generallyinclude the step of admixing a compound of the present invention withthe carrier, and optionally, one or more auxiliary agents. In the caseof a solid dosage form (e.g., capsules, tablets, pills, powders,granules, trouches, and the like), the active compound can be admixedwith a finely divided solid carrier, and typically, shaped, such as bypelletizing, tableting, granulating, powderizing, or coating. Generally,the solid carrier may include, for example, sodium citrate or dicalciumphosphate, and/or any of the following: (1) fillers or extenders, suchas starches, lactose, sucrose, glucose, mannitol, and/or silicic acid;(2) binders, such as, for example, carboxymethylcellulose, alginates,gelatin, polyvinyl pyrrolidone, sucrose and/or acacia; (3) humectants,such as glycerol; (4) disintegrating agents, such as agar-agar, calciumcarbonate, potato or tapioca starch, alginic acid, certain silicates,and sodium carbonate; (5) solution retarding agents, such as paraffin;(6) absorption accelerators, such as quaternary ammonium compounds andsurfactants, such as poloxamer and sodium lauryl sulfate; (7) wettingagents, such as, for example, cetyl alcohol, glycerol monostearate, andnon-ionic surfactants; (8) absorbents, such as kaolin and bentoniteclay; (9) lubricants, such as talc, calcium stearate, magnesiumstearate, solid polyethylene glycols, sodium lauryl sulfate, zincstearate, sodium stearate, stearic acid, and mixtures thereof; (10)coloring agents; and (11) controlled release agents such as crospovidoneor ethyl cellulose. In the case of capsules, tablets and pills, thepharmaceutical compositions may also comprise buffering agents. Solidcompositions of a similar type may also be employed as fillers in softand hard-shelled gelatin capsules using such excipients as lactose ormilk sugars, as well as high molecular weight polyethylene glycols andthe like.

A tablet may be made by compression or molding, optionally with one ormore auxiliary ingredients. Compressed tablets may be prepared usingbinder (for example, gelatin or hydroxypropylmethyl cellulose),lubricant, inert diluent, preservative, disintegrant (for example,sodium starch glycolate or cross-linked sodium carboxymethyl cellulose),surface-active or dispersing agent.

The tablets, and other solid dosage forms of the active agent, such ascapsules, pills and granules, may optionally be scored or prepared withcoatings and shells, such as enteric coatings and other coatings wellknown in the pharmaceutical-formulating art. The dosage form may also beformulated so as to provide slow or controlled release of the activeingredient therein using, for example, hydroxypropylmethyl cellulose invarying proportions to provide the desired release profile, otherpolymer matrices, liposomes and/or microspheres. The dosage form mayalternatively be formulated for rapid release, e.g., freeze-dried.

Generally, the dosage form is required to be sterile. For this purpose,the dosage form may be sterilized by, for example, filtration through abacteria-retaining filter, or by incorporating sterilizing agents in theform of sterile solid compositions which can be dissolved in sterilewater, or some other sterile injectable medium immediately before use.The pharmaceutical compositions may also contain opacifying agents andmay be of a composition that they release the active ingredient(s) only,or preferentially, in a certain portion of the gastrointestinal tract,optionally, in a delayed manner. Examples of embedding compositions thatcan be used include polymeric substances and waxes. The activeingredient can also be in micro-encapsulated form, if appropriate, withone or more of the above-described excipients.

Liquid dosage forms are typically a pharmaceutically acceptableemulsion, microemulsion, solution, suspension, syrup, or elixir of theactive agent. In addition to the active ingredient, the liquid dosageform may contain inert diluents commonly used in the art, such as, forexample, water or other solvents, solubilizing agents and emulsifiers,such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethylacetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butyleneglycol, oils (in particular, cottonseed, groundnut, corn, germ, olive,castor and sesame oils), glycerol, tetrahydrofuryl alcohol, polyethyleneglycols and fatty acid esters of sorbitan, and mixtures thereof.

Dosage forms specifically intended for topical or transdermaladministration can be in the form of, for example, a powder, spray,ointment, paste, cream, lotion, gel, solution, or patch. Ophthalmicformulations, such as eye ointments, powders, solutions, and the like,are also contemplated herein. The active compound may be mixed understerile conditions with a pharmaceutically-acceptable carrier, and withany preservatives, buffers, or propellants that may be required. Thetopical or transdermal dosage form may contain, in addition to an activecompound of this invention, one or more excipients, such as thoseselected from animal and vegetable fats, oils, waxes, paraffins, starch,tragacanth, cellulose derivatives, polyethylene glycols, silicones,bentonites, silicic acid, talc and zinc oxide, and mixtures thereof.Sprays may also contain customary propellants, such aschlorofluorohydrocarbons and volatile unsubstituted hydrocarbons, suchas butane and propane.

For purposes of this invention, transdermal patches may provide theadvantage of permitting controlled delivery of a compound of the presentinvention into the body. Such dosage forms can be made by dissolving ordispersing the compound in a suitable medium. Absorption enhancers canalso be included to increase the flux of the compound across the skin.The rate of such flux can be controlled by either providing arate-controlling membrane or dispersing the compound in a polymer matrixor gel.

Pharmaceutical compositions of this invention suitable for parenteraladministration generally include one or more compounds of the inventionin combination with one or more pharmaceutically-acceptable sterileisotonic aqueous or nonaqueous solutions, dispersions, suspensions oremulsions, or sterile powders that may be reconstituted into sterileinjectable solutions or dispersions prior to use, which may containsugars, alcohols, antioxidants, buffers, bacteriostats, or solutes thatrender the formulation isotonic with the blood of the intendedrecipient.

In some cases, in order to prolong the effect of a drug, it may bedesirable to slow the absorption of the drug from subcutaneous orintramuscular injection. This may be accomplished by the use of a liquidsuspension of crystalline or amorphous material having poor watersolubility. The rate of absorption of the drug then depends upon itsrate of dissolution which, in turn, may depend upon crystal size andcrystalline form. Alternatively, delayed absorption of aparenterally-administered drug form is accomplished by dissolving orsuspending the drug in an oil vehicle.

Injectable depot forms can be made by forming microencapsule matrices ofthe active compound in a biodegradable polymer, such aspolylactide-polyglycolide. Depending on the ratio of drug to polymer,and the nature of the particular polymer employed, the rate of drugrelease can be controlled. Examples of other biodegradable polymersinclude poly(orthoesters) and poly(anhydrides). Depot injectableformulations can also be prepared by entrapping the drug in liposomes ormicroemulsions that are compatible with body tissue.

The pharmaceutical composition may also be in the form of amicroemulsion. In the form of a microemulsion, bioavailability of theactive agent may be improved. Reference is made to Dordunoo, S. K., etal., Drug Development and Industrial Pharmacy, 17(12), 1685-1713, 1991,and Sheen, P. C., et al., J. Pharm. Sci., 80(7), 712-714, 1991, thecontents of which are herein incorporated by reference in theirentirety.

The pharmaceutical composition may also contain micelles formed from acompound of the present invention and at least one amphiphilic carrier,in which the micelles have an average diameter of less than about 100nm. In some embodiments, the micelles have an average diameter less thanabout 50 nm, or an average diameter less than about 30 nm, or an averagediameter less than about 20 nm.

While any suitable amphiphilic carrier is considered herein, theamphiphilic carrier is generally one that has been grantedGenerally-Recognized-as-Safe (GRAS) status, and that can both solubilizethe compound of the present invention and microemulsify it at a laterstage when the solution comes into a contact with a complex water phase(such as one found in the living biological tissue). Usually,amphiphilic ingredients that satisfy these requirements have HLB(hydrophilic to lipophilic balance) values of 2-20, and their structurescontain straight chain aliphatic radicals in the range of C-6 to C-20.Some examples of amphiphilic agents include polyethylene-glycolizedfatty glycerides and polyethylene glycols.

Particularly preferred amphiphilic carriers are saturated andmonounsaturated polyethyleneglycolyzed fatty acid glycerides, such asthose obtained from fully or partially hydrogenated various vegetableoils. Such oils may advantageously consist of tri-, di- and mono-fattyacid glycerides and di- and mono-polyethyleneglycol esters of thecorresponding fatty acids, with a particularly preferred fatty acidcomposition including capric acid 4-10, capric acid 3-9, lauric acid40-50, myristic acid 14-24, palmitic acid 4-14 and stearic acid 5-15%.Another useful class of amphiphilic carriers includes partiallyesterified sorbitan and/or sorbitol, with saturated or mono-unsaturatedfatty acids (SPAN-series) or corresponding ethoxylated analogs(TWEEN-series). Commercially available amphiphilic carriers areparticularly contemplated, including the Gelucire®-series, Labrafil®,Labrasol®, or Lauroglycol®, PEG-mono-oleate, PEG-di-oleate,PEG-mono-laurate and di-laurate, Lecithin, Polysorbate 80.

Hydrophilic polymers suitable for use in the pharmaceutical compositionare generally those that are readily water-soluble, can be covalentlyattached to a vesicle-forming lipid, and that are tolerated in vivowithout substantial toxic effects (i.e., are biocompatible). Suitablepolymers include, for example, polyethylene glycol (PEG), polylactic(also termed polylactide), polyglycolic acid (also termedpolyglycolide), a polylactic-polyglycolic acid copolymer, and polyvinylalcohol. Preferred polymers are those having a molecular weight of fromabout 100 or 120 daltons up to about 5,000 or 10,000 daltons, and morepreferably from about 300 daltons to about 5,000 daltons. In aparticularly preferred embodiment, the polymer is polyethylene glycolhaving a molecular weight of from about 100 to about 5,000 daltons, andmore preferably having a molecular weight of from about 300 to about5,000 daltons, or a molecular weight of 750 daltons, i.e., PEG(750).Polymers may also be defined by the number of monomers therein. Apreferred embodiment of the present invention utilizes polymers of atleast about three monomers, such PEG polymers consisting of at leastthree monomers, or approximately 150 daltons. Other hydrophilic polymersthat may be suitable for use in the present invention includepolyvinylpyrrolidone, polymethoxazoline, polyethyloxazoline,polyhydroxypropyl methacrylamide, polymethacrylamide,polydimethylacrylamide, and derivatized celluloses such ashydroxymethylcellulose or hydroxyethylcellulose.

In certain embodiments, the pharmaceutical composition includes abiocompatible polymer selected from polyamides, polycarbonates,polyalkylenes, polymers of acrylic and methacrylic esters, polyvinylpolymers, polyglycolides, polysiloxanes, polyurethanes and co-polymersthereof, celluloses, polypropylene, polyethylenes, polystyrene, polymersof lactic acid and glycolic acid, polyanhydrides, poly(ortho)esters,poly(butic acid), poly(valeric acid), poly(lactide-co-caprolactone),polysaccharides, proteins, polyhyaluronic acids, polycyanoacrylates, andblends, mixtures, and copolymers thereof.

The pharmaceutical composition may also be in liposomal form. Liposomescontain at least one lipid bilayer membrane enclosing an aqueousinternal compartment. Liposomes may be characterized by membrane typeand by size. Small unilamellar vesicles (SUVs) have a single membraneand typically range from 0.02 to 0.05 μm in diameter; large unilamellarvesicles (LUVS) are typically larger than 0.05 μm Oligolamellar largevesicles and multilamellar vesicles have multiple, usually concentric,membrane layers, and are typically larger than 0.1 μm. The liposomes mayalso contain several smaller vesicles contained within a larger vesicle,i.e., multivesicular vesicles.

In some embodiments, the pharmaceutical composition includes liposomescontaining a compound of the present invention, where the liposomemembrane is formulated to provide an increased carrying capacity.Alternatively or in addition, the compound of the present invention maybe contained within, or adsorbed onto, the liposome bilayer of theliposome. In some embodiments, the active agent may be aggregated with alipid surfactant and carried within the liposome's internal space. Insuch cases, the liposome membrane is preferably formulated to resist thedisruptive effects of the active agent-surfactant aggregate. In aparticular embodiment, the lipid bilayer of a liposome contains lipidsderivatized with polyethylene glycol (PEG), such that the PEG chainsextend from the inner surface of the lipid bilayer into the interiorspace encapsulated by the liposome, and extend from the exterior of thelipid bilayer into the surrounding environment.

Active agents contained within liposomes of the present invention arepreferably in solubilized form. Aggregates of surfactant and activeagent (such as emulsions or micelles containing the active agent ofinterest) may be entrapped within the interior space of liposomesaccording to the present invention. A surfactant typically serves todisperse and solubilize the active agent. The surfactant may be selectedfrom any suitable aliphatic, cycloaliphatic or aromatic surfactant,including but not limited to biocompatible lysophosphatidylcholines(LPCs) of varying chain lengths, e.g., from about 14 to 20 carbons).Polymer-derivatized lipids, such as PEG-lipids, may also be utilized formicelle formation as they will act to inhibit micelle/membrane fusion,and as the addition of a polymer to surfactant molecules decreases thecritical micelle concentration (CMC) of the surfactant and aids inmicelle formation. Preferred are surfactants with CMCs in the micromolarrange; higher CMC surfactants may be utilized to prepare micellesentrapped within liposomes of the present invention, however, micellesurfactant monomers could affect liposome bilayer stability and would bea factor in designing a liposome of a desired stability.

Liposomes according to the present invention may be prepared by any of avariety of techniques known in the art, such as described in, forexample, U.S. Pat. No. 4,235,871 and International Published ApplicationWO 96/14057, the contents of which are incorporated herein by referencein their entirety. For example, liposomes may be prepared by diffusing alipid derivatized with a hydrophilic polymer into preformed liposomes,such as by exposing preformed liposomes to micelles composed oflipid-grafted polymers, at lipid concentrations corresponding to thefinal mole percent of derivatized lipid which is desired in theliposome. Liposomes containing a hydrophilic polymer can also be formedby homogenization, lipid-field hydration, or extrusion techniques, asare known in the art. By another methodology, the active agent is firstdispersed by sonication in a lysophosphatidylcholine or other lowcritical micelle concentration (CMC) surfactant (including polymergrafted lipids) that readily solubilizes hydrophobic molecules. Theresulting micellar suspension of active agent is then used to rehydratea dried lipid sample that contains a suitable mole percent ofpolymer-grafted lipid, or cholesterol. The lipid and active agentsuspension is then formed into liposomes using extrusion techniques wellknown in the art, and the resulting liposomes separated from theunencapsulated solution by standard column separation.

In one aspect of the present invention, the liposomes are prepared tohave substantially homogeneous sizes in a selected size range. Oneeffective sizing method involves extruding an aqueous suspension of theliposomes through a series of polycarbonate membranes having a selecteduniform pore size. The pore size of the membrane will correspond roughlywith the largest sizes of liposomes produced by extrusion through themembrane (U.S. Pat. No. 4,737,323, the contents of which are hereinincorporated by reference in their entirety).

The release characteristics of a formulation of the present inventiondepend on several factors, including, for example, the type andthickness of the encapsulating material, the concentration ofencapsulated drug, and the presence of release modifiers. If desired,the release can be manipulated to be pH dependent, such as by using apH-sensitive coating that releases only at a low pH, as in the stomach,or releases at a higher pH, as in the intestine. An enteric coating canbe used to prevent release from occurring until after passage throughthe stomach. Multiple coatings or mixtures of cyanamide encapsulated indifferent materials can be used to obtain an initial release in thestomach, followed by later release in the intestine. Release can also bemanipulated by inclusion of salts or pore-forming agents, which canincrease water uptake or release of drug by diffusion from the capsule.Excipients that modify the solubility of the drug can also be used tocontrol the release rate. Agents that enhance degradation of the matrixor release from the matrix can also be incorporated. The agents can beadded to the drug, added as a separate phase (i.e., as particulates), orcan be co-dissolved in the polymer phase depending on the compound. Inall cases, the amount is preferably between 0.1 and thirty percent (w/wpolymer). Some types of degradation enhancers include inorganic salts,such as ammonium sulfate and ammonium chloride; organic acids, such ascitric acid, benzoic acid, and ascorbic acid; inorganic bases, such assodium carbonate, potassium carbonate, calcium carbonate, zinccarbonate, and zinc hydroxide; organic bases, such as protamine sulfate,spermine, choline, ethanolamine, diethanolamine, and triethanolamine;and surfactants, such as a Tween™ or Pluronic™ commercial surfactant.Pore-forming agents that add microstructure to the matrices (i.e.,water-soluble compounds, such as inorganic salts and sugars) aregenerally included as particulates.

Uptake can also be manipulated by altering residence time of theparticles in the body. This can be achieved by, for example, coating theparticle with, or selecting as the encapsulating material, a mucosaladhesive polymer. Examples include most polymers with free carboxylgroups, such as chitosan, celluloses, and especially polyacrylates (asused herein, polyacrylates refers to polymers including acrylate groupsand modified acrylate groups such as cyanoacrylates and methacrylates).

In another aspect, the invention provides an assay method foridentifying a compound that binds to a lipofuscin bisretinoid lipid(e.g., A2E or derivative thereof). The method makes use of the knownfluorescing ability of lipofuscin bisretinoid lipids, and thesensitivity of their fluorescing characteristics (e.g., emissionwavelength) on the immediate environment. By virtue of this sensitivity,a lipofuscin bisretinoid lipid that is not bound or complexed to aparticular substance (i.e., candidate compound) will show a differentemission wavelength under the same conditions to the same lipofuscinbisretinoid lipid bound or complexed to the substance.

In the assay method, at least two solutions containing a lipofuscinbisretinoid lipid are first provided, and the at least two solutionsshould be substantially the same in all respects, such as in the type oflipofuscin bisretinoid lipid, the concentration of lipofuscinbisretinoid lipid, and the solvent composition. A candidate compound isthen added to at least one of the solutions. Fluorescence spectra of thetwo solutions (i.e., a first solution not containing the candidatecompound and a second solution containing the candidate compound) isthen measured at an excitation wavelength (e.g., 434 nm or othersuitable excitation wavelength) that causes fluorescence of thelipofuscin bisretinoid lipid in the range of 530 nm and 700 nm, or anysuitable sub-range therein. An area under the curve (AUC) is thendetermined for corresponding spectral curves of the first and secondsolutions within the range of 530 nm and 700 nm or a sub-range therein.The corresponding spectral curves should be in the same wavelengthrange. A ratio of the AUC of the second solution (containing thecandidate compound) over the AUC of the first solution (not containingthe candidate compound) is then calculated. A ratio greater than 1indicates that the candidate compound has bound to or complexed with thelipofuscin bisretinoid lipid, and a ratio of 1 or less indicates thatthe candidate compound has not bound to or complexed with (e.g., byhost-guest complexation) the lipofuscin bisretinoid lipid. The candidatecompound can be any compound for which lipofuscin bisretinoid lipidbinding activity is to be confirmed. In particular embodiments, thecandidate compound is a cyclic oligosaccharide, or more particularly, acyclodextrin.

In some embodiments, the assay method described above is practiced in ahigh-throughput screening (HTS) mode. Methods and details for practicinga HTS process are well known in the art, particularly in thepharmaceutical arts, as particularly used for accelerating drugdiscovery. The HTS process generally employs an assay plate, typically amicrotiter plate, containing a multiplicity of wells in which the assayreactions are conducted. In the HTS process, numerous reactions andmeasurements can be made at once, or efficiently over a short period oftime. The HTS process is often automated in one or more aspects.

Other means for identifying or optimizing compounds for encapsulating orhaving an increased affinity for lipofuscin bisretinoid lipid (e.g.,A2E) are considered herein. For example, either coupled with thefluorometric assay above or as an independent endeavor, a molecularfitting study can be undertaken to determine structural features neededto optimize encapsulation or binding affinity of A2E. This may involvemolecular modeling to understand in better detail the interaction of thelipofuscin bisretinoid lipid with the hydrophobic core of the cyclicoligosaccharide. The interaction between a potential chemical host(complexant) and A2E may also be analyzed by a physical method, such asnuclear magnetic resonance spectroscopy (NMR) or microcalorimetry.

Examples have been set forth below for the purpose of illustration andto describe the best mode of the invention at the present time. However,the scope of this invention is not to be in any way limited by theexamples set forth herein.

Example 1 Assay for Molecules with Ability to Encapsulate A2E

As shown in FIG. 4, A2E fluorescence changes according to the polarityof its environment. Based on this principle, a screening method washerein developed to identify molecules with the ability to encapsulateA2E.

As shown in FIG. 5, A2E fluorescence changes when incubated withbeta-cyclodextrins and gamma-cyclodextrins, but does not change whenincubated with the alpha-cyclodextrins tested. This result indicatesthat the smaller interior cavity of alpha-cyclodextrins is eithersignificantly hindered in hosting or complexing A2E or may not becapable of accommodating A2E altogether. The results also indicate thatthe larger cavities of beta- and gamma-cyclodextrins are much moresuited for forming a host-guest complex with A2E.

As shown in FIG. 5, A2E was in a final concentration of 5 μM in 200 μlaliquots of 10 mM cyclic oligosaccharide solutions in quadruplicate. Thefluorescence spectra were immediately determined (although it was stablefor several days) between 530 and 700 nm using a 434 nm excitationwavelength. For inter-assay reproducibility, a sample of A2E (5 μM) inethanol was run in each assay to normalize and compare solvatochromicshifts obtained on different days. The area under the resulting spectralfluorescence curve was determined with statistical software (Prism4,GraphPad). If the ratio of the area under the curve (AUC) for a testedcompound over the AUC for A2E alone in the same aqueous phase is higherthan 1, then it indicates that the cyclic oligosaccharide isencapsulating A2E. As the AUC ratios reflect the ability to form betterinclusion complexes with A2E, this method easily reveals if a givencompound is superior to one already developed, thus allowingidentification of new active agents. No interaction will be consideredwhen the area under the curve (AUC) is equal to 1. Based on the datacollected with this method, mathematical models can be developed todetermine the inclusion complex formation constants and stoichiometricconstants. The assay method is valuable as a rapid screening method tocharacterize inclusion complexes between A2E and cyclic oligosaccharidesand can be easily adapted for high-throughput screening (HTS). Themethod can be extended for the screening of compounds able to host orbind to other fluorescent molecules.

A library of cyclodextrins, as listed in Table 1 below, was investigatedusing this assay method.

TABLE 1 Library of cyclodextrin candidate compounds Com- pound #Cyclodextrin Structure  1 α-cyclodextrin (α-CD) Sigma-Aldrich # C4680Synonym: α-Schardinger dextrin, Cyclohexaamylose, CyclomaltohexaoseLinear Formula: C36H60O30 Molecular Weight: 972.84 CAS Number:10016-20-3

 2 Carboxymethyl α-cyclodextrin Sigma-Aldrich # ELDEXACID-kit CYCLOLABLtd.# CY-E- 1006.0

 3 Carboxyethyl α-cyclodextrin Sigma-Aldrich # ELDEXACID-kit CYCLOLABLtd.# CY-E- 1012.0

 4 β-cyclodextrin (β-CD) Sigma-Aldrich # C4805 Synonym: Caraway,Cycloheptaamylose, Cyclomaltoheptaose, Schardinger β-Dextrin LinearFormula: C42H70O35 Molecular Weight: 1134.98 CAS Number: 7585-39-9

 5 Methyl-β-cyclodextrin Sigma Aldrich # 332615 CAS Number: 128446-36-6average Mn 1310 (Aldrich)

 6 Heptakis(2,3,6-tri-O-methyl)- β-cyclodextrin Sigma-Aldrich # 51707Synonym: 2,3,6-Tri-O-methyl- β-cyclodextrin, Trimethyl-β- cyclodextrinLinear Formula: C63H112O35 Molecular Weight: 1429.54 CAS Number:55216-11-0

 7 (2-Hydroxypropyl)-β- cyclodextrin Sigma-Aldrich 332593 CAS Number:128446-35-5

 8 Succinyl-β-cyclodextrin Sigma Aldrich # 85990 MDL number:MFCD00800297 PubChem Substance ID: 24888494

 9 β-Cyclodextrin polymer, soluble Sigma Aldrich # C2485 Molecular wtdistribution: 2,000 to 15,000

10 Poly-beta-cyclodextrin crosslinked with epichlorohydrin TCI # P0977

11 Quaternary β-cyclodextrin Sigma Aldrich # (Supelco) 33805

12 Triacetyl-β-cyclodextrin Sigma Aldrich # 332623 Synonym:β-Cyclodextrin heneicosaacetate Linear Formula: C84H112O56 MolecularWeight: 2017.75 CAS Number: 23739-88-0

13 6-O-α-Maltosyl-β-cyclodextrin hydrate Sigma Aldrich # M9672 LinearFormula: C54H90O45 Molecular Weight: 1459.27 CAS Number: 104723-60-6

14 Heptakis(2,6-di-O-methyl)-β- cyclodextrin Sigma-Aldrich # H0513Synonym: 2,6-Di-O-methyl-β- cyclodextrin, Dimethyl β- cyclodextrinLinear Formula: C56H98O35 Molecular Weight: 1331.36 CAS Number:51166-71-3

15 Carboxymethyl-β-cyclodextrin Sigma-Aldrich # ELDEXACID-Kit CYCLOLABLtd.# CY-E- 2006.0

16 Carboxyethyl β-cyclodextrin Sigma-Aldrich # ELDEXACID-kit CYCLOLABLtd.# CY-E- 2012.0

17 γ-cyclodextrin (γ-CD) Sigma-Aldrich # C4892 Synonym:Cyclomaltooctaose, Cyclooctaamylose, Schardinger γ-Dextrin LinearFormula: C48H80O40 Molecular Weight: 1297.12 CAS Number: 17465-86-0

18 γ-Cyclodextrin polymer, soluble Sigma Aldrich # C2860

19 γ-Cyclodextrin phosphate sodium salt Sigma-Aldrich (FLUKA) # 90727CAS Number: 199684-62-3

20 (2-Hydroxypropyl)-γ- cyclodextrin Sigma-Aldrich # H125 Synonym: HGCCAS Number: 128446-34-4

21 Carboxymethyl γ-cyclodextrin Sigma-Aldrich # ELDEXACID-kit CYCLOLABLtd.# CY-E- 3006.0

FIG. 6 shows a graphical plot of the AUC calculated for each of the 21cyclodextrin candidate compounds. The graphical plots shown in FIGS. 6and 7 show that some of the cyclodextrins are active or highly active(i.e., by exhibiting a AUC ratio greater than 1), whereas othercyclodextrins are not sufficiently active (i.e., by exhibiting a AUCratio of or less than 1).

Example 2 Comparison of Cyclodextrin Binding to A2E and to DHE

The binding of A2E and DHE (fluorescent cholesterol analog tocyclodextrins) has been herein investigated by using the assay methoddescribed above. FIG. 9A shows fluorescence spectra changes of DHE andA2E as a function of added β-CD concentration derivative. Such changesare indicative of the penetration of DHE or A2E into the hydrophobicβ-CD cavities resulting in the formation of DHE-β-CD and A2E-β-CDinclusion complexes. FIG. 9B shows the fluorescence of DHE and A2E atdifferent CD:fluorescent guest ratios. The determination of affinityconstants and stoichiometry for new inclusion complexes can be complex,particularly when the molecular ratio host:guest is bigger than 1. Forcholesterol, however, the affinity constants, stoichiometry, molecularstructure, and applications of many of its inclusion complexes withcyclic oligosaccharides have been well established. In this context, theside-by-side comparation of A2E and cholesterol complex formation withthe same cyclic oligosaccharide serves as an immediate reference toevaluate the quality of the inclusion complex with A2E, as well as helpin the determination of its affinity constant, stoichiometry, andstructure.

Example 3 Computer Modeling of Interaction Between Cyclodextrins and A2E

Molecular Mechanics (MM+) was used to investigate the process ofinclusion of A2E into the β-CD cavity, and the stability of theinclusion complexes formed were ascertained by their energy of formationvalues. Theoretical studies were conducted on the parent β-CD and A2Eonly. In the study, it was assumed that the basic closed structure ofβ-CD is maintained in A2E-CD. Schroedinger Suite™ was used to build thestructure of A2E and β-CD molecules. A2E β-CD was built on-screen usingmolecular design software/Pymol, and β-CD monomer was downloaded as PDBcoordinates. The structures of A2E-β-CD complexes were considered in thegaseous state and the molecular mechanics program MM+ implemented in thesoftware package was used to minimize them. No cut-offs were used andgeometry optimization was made to an energy convergence of 0.01 kcal/Aper mol with the Polak-Ribiere conjugate gradient algorithm.

Docking calculations were performed in vacuo to locate the low energystructures for the A2E-β-CD complexes. Two principal relativearrangements of A2E and β-CD were considered. In one case, the A2Emolecule was allowed to approach the β-CD cavity from the wider rim,which contains the secondary hydroxyl groups, while in the other, it wasmade to approach the β-CD cavity from the primary hydroxyl rim. Theinitial A2E configuration was parallel to the β-CD hydroxyl rim at adistance of about 2 Å from the rim. A2E was then manually rotated bysteps of 45° and an optimization was set to start after each rotation.Each of these stochastically-generated low-energy structures were thengrouped so as to identify the path of entry of A2E into the β-CD cavityand the nature of complex formed with β-CD. This work provides the basisfor a preferred embodiment in which the cyclic oligosaccharide ismultimeric.

Example 4 A2E Oxidation Assay

Solutions containing increasing amounts of Poly Beta-CD (0 mM to 100 mM)were prepared in water, and A2E was added to a final concentration of 5μM. The solutions were incubated at RT in the dark. 48 hrs later, theUV-visible absorption spectra between 300 and 700 nm was analyzed todetermine the oxidative status of A2E. The UV-visible spectrum of A2Eexhibits two major absorbance bands at 337 nm and 438 nm. These bandscan be assigned to the shorter (S) and longer (L) arms of A2E,respectively. Oxidation of a carbon-carbon double bond is accompanied bya hypsochromic shift. A hypsochromic shift in band S corresponds withoxidation on the short arm; a blue-shift in band L reflects oxidation onthe long arm; hypsochromic shifts in both peaks indicates oxidation onboth side arms (Jang Y. P. et al., J. Biol. Chem., 2005,280(48):39732-9). The results shown in FIG. 12A indicate that under thisaqueous environment A2E oxidizes. However, the results shown in FIG. 12Balso demonstrate that the formation of the inclusion complex with CDsprotect against this event.

Example 5 A2E Aggregation Assay

A2E aggregates are believed to have a role in RPE cell death. This studyinvestigated whether cyclic oligosaccharides dissolve A2E aggregatesthat form in aqueous phase. The following can be deduced from FIG. 13:

A) Predicted size (<0.005 um) of A2E molecule based on its molecularweight (596).

B) Differential Interference Contrast (DIC) microscopy, combined withfluorescence microscopy, shows that A2E aggregates to form crystals ofseveral microns in size when in aqueous phase, both in cell free and(left panel) and within RPE cells (right panel). A2E was added to thecells at 25 μM final concentration for three days.

C) Transwell with 0.4 μm and 3 μm pores were inserted in 12-well plates,and A2E was added to the media in only one side of the membrane. Afterthree days, the liquid in each chamber was harvested and analyzed with aspectrofluorometer to detect the presence of A2E. Only inserts with 3 μmpores allowed A2E to diffuse through.

D) Using similar principles, it was demonstrated that A2E in 25 μMaqueous solutions cannot pass through 0.2 μm pore filters. In contrast,addition of cyclodextrins to the A2E aqueous solution dissolved the A2Eaggregates, thereby allowing A2E to diffuse through 0.2 μm pores. Thepresence of A2E on each side was established by fluorescence scanningbetween 530-700 nm using 434 nm as the excitation wavelength.

Example 6 Cell Assay of Cyclodextrin Efficacy

The aim of this study was to determine whether cyclic oligosaccharidesclear RPE cells from bisretinoids by encapsulating A2E. Briefly, ARPE-19cells, a human retinal-pigmented epithelial cell line, were grown inmedia containing A2E (25 μM final) for three days. Subsequently, thecells were washed twice and incubated for three days in media containing1 mM poly BetaCD and 10% FMS. After three more days, the content of A2Ewas compared by microscopy between A2E-loaded cells, treated andnon-treated with cyclodextrin (CD). As shown in FIGS. 14 and 15,administration of cyclic oligosaccharides causes a significant reductionin bisretinoids RPE cell content.

FIG. 15 shows that CDs can reduce A2E levels in highly confluent, wellpolarized, epithelia. In FIG. 15B, Panel A shows control epithelialcells loaded with A2E (bright fluorescence). Panel C shows polarizedepithelium extracted with CDs after 24 hours. The loss of fluorescentpigments is notable. Panels B and D are images of the same epitheliailluminated with white light to demonstrate that their integrity is notcompromised by treatment with CDs.

An excellent animal model to study retinal degeneration in response toaccumulation of bisretinoids is the recently developed RDH8/ABCA4-doubleknockout (DKO) mice, which exhibit accelerated A2E build up and displayprogressive retinal degeneration and blindness, with typical signs ofAMD such as “drusen” and thickened Bruch's membrane, by five weeks(Maeda, A., et al., Retinopathy in mice induced by disruptedall-trans-retinal clearance. J Biol Chem, 2008. 283(39): p. 26684-93).

Example 7 “In Vitro” Assay Showing that Cyclodextrins Effectively CleanBisretinoids from the Eye of DKO Mice

As indicated in FIG. 17A, eyes from DKO mice were enucleated anddissected to separate cornea, lens, iris and neuroretina from theposterior part of the eye (eyecups). Eyecups comprise the dark pigmentedRPE, choriocapillaries, as well as the grayish sclera. Eyecups wereincubated in complete media containing, or not, 2 mM cyclodextrins.After 36 hours of culture, eyecups were flat mounted on glasses andfluorescence was analyzed in the microscope. The lack of fluorescence ineyecups incubated with methyl beta-cyclodextrin is indicative of theability of CDs to remove bisretinoids from the eye's RPE.

A fundus camera or retinal camera is a specialized low power microscopewith an attached camera designed to photograph the interior surface ofthe eye, including the retina, optic disc, macula, and posterior pole(i.e. the fundus). Fundus cameras are used by optometrists,ophthalmologists, and trained medical professionals for monitoringprogression or diagnosis of a retinal disease. A typical camera views 30to 50 degrees of retinal area, with a magnification of 2.5×.

Color fundus examination is performed when the retina is illuminated bywhite light and the resulting image is consequently full colored. Itpermits detection of the extracellular deposits, called drusen,underneath the RPE that are among the earliest signs of retinaldysfunction.

Autofluorescence fundus is performed when the retina is illuminated byblue light of about 430 nm. The intensity of the resulting greenfluorescence permits semi-quantitative assessment of the amount ofbisretinoids accumulated in the RPE of the eye.

FIG. 16B shows fundus images obtained from eight month old WT control(A), DKO (B) and CD-treated DKO (C) mice. The clear dots (drusen) incolor fundus of DKO are notably reduced by CD treatment (compare D, E,and F). The right panels display the autofluorescence fundus images fromWT control (D), DKO (E), and CD-treated DKO (F) mice. The numbersindicate total amount of auto-fluorescence per mouse retina, which is adirect readout of the content of bisretionoids in RPE.Immunofluorescence examination of cryosected retinas show theeffectiveness of the treatment with cyclodextrins. Briefly, subtenontreatment with methyl beta-cyclodextrin reduced the amount ofautofluorescence in the RPE layer as well as the retinal detachment(compare untreated (b) with treated (c)). Thus, FIG. 16 shows that CDtreatment of DKO mice reduces fundus, drusen, and autofluorescence.

Example 8 Measurement of the Strength of the Interaction Between CDs andA2E

The fluorescence of A2E changes upon inclusion in the CD cavity, and themagnitude of this shift is related to the degree of binding. Therefore,using this information the dissociation constant (K_(d)) can bedetermined for the complexes of A2E with the different cyclodextrins byusing the Benesi-Hildebrand plot and calculations. Accordingly, theK_(d) is the ratio of the intersect/slope of the double reciprocal plot,1/(F−F₀) vs. 1/[CD] (see FIG. 6), where F₀ is the fluorescence intensityof A2E in water, and F is the fluorescence intensity of A2E in aparticular CD solution. The K_(d) data for the CD compounds in FIG. 7are tabulated in FIG. 6.

Example 9 Microscopic Views of Retinas of DKO Mice with and without CDTreatment

The retinas of wild type and DKO animals were analyzed by fluorescencemicroscopy with the following procedure. Briefly wild type and DKOanimals were mock-treated or treated with a single subtenon injectionwith either vehicle or with methyl beta-cyclodextrin (4000 mg/kg). After48 hours the eyes were enucleated, fixed, and cryosected. For viewing,10-micron thick sections were blocked and stained with thered-fluorescently labeled lectin PNA to identify cones in thephotoreceptor outer segments (PROS), and blue DAPI nuclear stain toidentify the nuclei. In the gray scale micrograph of FIG. 18 (Panel A),the red and blue stains are not distinguishable, so the red fluorescenceis labeled PROS and the lighter autofluorescent RPE is also labeled.(The blue nuclei are unlabeled, but are the dotted lighter region to theright of the PROS.) The retina from the mock treated DKO (panel B) mouseretina displays both retinal detachment, depicted by the arrow, andsubstantial RPE autofluoresence due to bisretinoids. Panel C shows theretina from the DKO mouse treated with methyl beta-cyclodextrin, whichdisplays reduced detachment and bisretinoid autofluorescence.

While there have been shown and described what are at present consideredthe preferred embodiments of the invention, those skilled in the art maymake various changes and modifications which remain within the scope ofthe invention defined by the appended claims.

What is claimed is:
 1. A method for treating a subject suffering from adisorder characterized by the intracellular accumulation of lipofuscinbisretinoid lipids in retinal pigment epithelial (RPE) cells, the methodcomprising administering to said subject a therapeutically-effectiveamount of a (2-hydroxypropyl)-beta-cyclodextrin that targets retinalpigment epithelium cells and has an available binding cavity that is notcomplexed with a guest molecule when administered and that complexeslipofuscin bisretinoid lipids in said retinal pigment epithelium cells,wherein said disorder is selected from Stargardt disease, Best disease,retinitis pigmentosa, and cone-rod dystrophy.
 2. The method of claim 1,wherein the method prevents lipofuscin-associated retinal damage fromworsening in said subject suffering from lipofuscin-associated retinaldamage.
 3. The method of claim 1, wherein the method reverses symptomsof said disorder associated with lipofuscin-associated retinal damage.4. The method of claim 1, wherein the method stops, mitigates, orreverses accumulation of lipofuscin in retinal pigment epithelium cells.5. The method of claim 1, wherein said lipofuscin bisretinoid lipid isselected from N-retinylidene-N-retinylethanolamine (A2E), an A2E isomer,an oxidized derivative of A2E, and all-trans-retinal dimers.
 6. Themethod of claim 1, wherein said (2-hydroxypropyl)-beta-cyclodextrin iscoupled to an agent that targets retinal pigment epithelium cells. 7.The method of claim 6, wherein said agent targets endosomes or lysosomesin said retinal pigment epithelium cells.
 8. The method of claim 6,wherein said agent is mannose 6-phosphate.
 9. The method of claim 1,wherein the (2-hydroxypropyl)-beta-cyclodextrin is administered bytopical, intravitreous, subretinal, or subscleral administration. 10.The method of claim 9, wherein said subscleral administration isachieved by implanting in said subject a slow-release subscleralimplant.
 11. The method of claim 1, wherein said disease or condition isStargardt disease.